Biomimetic saddle structure

Abstract

A saddle 211 with a saddle tree 213 having a plurality of contact pads disposed laterally along a central axis of the core tree. Connecting members connect the core tree to the contact pads. In use, the core tree is placed alone a horse’s spine, and the contact pads contact the horse’s back. The contact pads may be square shape, and may be front 219, middle 221 or rear 223 plate members. The position and angle of the contact pads may change relative to the position and / or angle of the core tree, responsive to the position and extent of load applied to saddle. This more evenly spreads the load and reduces pressure points in a horse for a more comfortable ride, improved animal welfare and a reduced risk of discomfort or injury to the horse. The frame may also have a gullet bar 207 or head portion 217. The core tree or connecting members may be substantially rigid. There may be an articulating arrangement linking the contact pads to the connecting members.

Description

FIELD OF THE INVENTION The present invention relates to the field of saddle trees for use in the manufacture of saddles for horses and, in particular, to a saddle structure comprising a core saddle tree that improves the load spreading of a dynamic load onto a horse, to components thereof, and to methods of constructing saddles using the saddle tree or saddle tree structure. BACKGROUND OF THE INVENTION Saddle trees are used in the manufacture of saddles to provide strength and structural support and providing a core or base about which a saddle may be built. A conventional saddle tree for a riding saddle comprises a frame formed from wooden parts, including two generally parallel (and symmetrically disposed) longitudinal side bars spaced apart to be disposed either side of a horse’s spine and these side bars are linked together at the fore by a head portion that forms the headplate (or forks) and at the rear by a cantie. Typically, metal supports of sprung steel are provided, extending front to back, and steel gullet bars may also be provided to provide rigidity at the headplate or pommel of the resulting saddle. Traditional saddle manufacture involves the saddle maker shaping and forming the saddle to provide the form of the saddle within the confines of the saddle tree shape, then lining with rubber or synthetic rubber and / or dense foam components or with wool or foam-stuffed panels, which are further shaped for horse and rider fit and rider preference and to provide the base upon which the saddle outer (typically of leather) may be built. Ideally, the saddle will be configured to fit the particular horse (as well as a rider). The wool or foam-stuffed panels on the underside of the saddle serve to provide load-bearing contact with the back of the horse, along the horse’s back on either side of the spine, ensuring the weight of the saddle is not upon the horse’s spine. The stuffed loadbearing panels generally rest on the thoracic region shy of the shoulder blades of the horse and without any load-bearing to the posterior of the last rib (i.e. the lumbar area of the horse should generally not be load bearing). Notwithstanding a traditional saddle being made with a good fit, traditional saddles do not allow for changes in a horse’s shape that occur as it moves, or changes in the load from riders with different riding styles or even a single rider in different positions. The lack of dynamic support can cause pain, restrict movement of the horse and potentially lead to either physiological or behavioural problems for the horse or constrain the horse’s performance. Several attempts have been made to improve saddle fit and address the aforementioned problems. WO-A-2010 / 079354 describes a ‘treeless’ saddle which has a dynamic load distribution system. The saddle includes several load-bearing sections positioned upon two flexible inner side panels. Line guides are fixed to the sections and load distribution lines pass through the guides, and loop around free-running pulleys of the stirrup hanger system. A stirrup hanger bar includes diverter pulleys and cooperates with a pulley block to transfer loads through the load-distribution lines to the load-bearing sections around the saddle. The girthing system of the saddle includes webbing members attached to the load-bearing sections. The webbing members are connected to the ends of the girth straps so that the load is transferred from the girth straps to the load-bearing sections on each side of the saddle. The dynamic load distribution system reduces localised load pressure points and permits flexing of the animal’s spine. WO-A-2016 / 181151 describes a saddle structure having aplurality of transverse rib members each having a central crown portion, the saddle structure having a spine member connected to each pair of adjacent crown portions and having sufficient flexibility to flex with the flexure of the spine of the animal. Accordingly, when the horse moves, the flexibility along the spine member of the saddle structure serves to enable the saddle to adapt to the movement of the horse. WO-A-2016 / 181151 is not consistent with traditional saddle manufacture. WO-A-2008 / 030103 is directed to a saddle that is configured with at least three longitudinally disposed component parts, the fore and rear parts rotatably hingedly mounted (about a vertical axis) onto the middle part along a central axis whereby the fore and rear parts will articulate relative to the middle part as the horse moves. Thus, the saddle will conform to the back of the animal as its moves while providing stability and a continuous surface against the back of the animal. The foremost part is said to be adjustable to allow the saddle to fit different widths of animal. The saddle arrangement of WO-A-2008 / 030103 is not consistent with conventional saddle manufacture techniques and could not readily be substituted into current processes. The present inventors have identified a solution by providing a saddle structure for a saddle which addresses the aforementioned shortcomings. PROBLEM TO BE SOLVED BY THE INVENTION It is an object of the invention to provide an improved saddle, saddle tree and saddle structure. It is an object of the invention to provide a saddle structure for manufacture of a saddle which provides an improved spread of load to the horse. It is an object of the invention to provide a saddle structure and saddle tree for a saddle, which adapts to or accommodates the movement of a horse and of a load on the horse. It is an object of the invention to provide a synthetic saddle tree and saddle structure which meets the support and flexibility requirements of a saddle tree and can be adopted in the traditional methods of saddle manufacture. SUMMARY OF THE INVENTION In accordance with a first aspect of the invention, there is provided a saddle structure comprising: a core tree configured for disposal, typically within a saddle, along a length of, and centered around, a horse’s spine; a plurality of contact pads disposed laterally of a central axis of the core tree and disposed along the length of the core tree, for contacting with a horse’s back; and one or more connecting members configured to connect the core tree to the contact pads, wherein the saddle structure is configured such that the position and / or angle of the pads may change, relative to the position and / or angle of the core tree, which is preferably responsive to the position and extent of load applied to a saddle in use. In a second aspect of the invention, there is provided a kit of parts comprising a core tree, a plurality of contact pads and one or more connecting members configured for mounting to the core tree and connecting to the contact pads, which parts may be assembled to form the saddle structure as defined above. In a third aspect of die invention, there is provided a mounting system for a saddle structure as defined above, the mounting system comprising a plurality7 of contact pads configured to be disposed laterally and along a length of a central axis of a core tree (or saddle tree) for supporting the core tree (or saddle tree) in contacting with a horse’s back; and one or more connecting members configured to connect the core tree (or saddle tree) to the contact pads, whereby when connected to a core tree (or saddle tree) and fitted to a horse the mounting system is configured such that the position and / or angle of the or each of contacting pads may change, relative to the position and / or angle of the core tree (or saddle tree), which is preferably responsive to the position and extent of load applied to a saddle in use. In a fourth aspect of the invention, there is provided a mounting structure for contact pads for use in the saddle structure defined above, the mounting structure comprising one or more connecting members configured for mounting to a core tree (or saddle tree) and connecting to a plurality of contact pads of the mounting structure. In a fifth aspect of the invention, there is provided a contact pad configured for connecting to one or more connecting members for connecting them to a saddle tree (or core tree) and configured such that its position and / or angle may change, relative to a position and / or angle of the saddle tree (or core tree), responsive to the position and extent of load applied to a saddle fitted with the saddle tree (or core tree), in use. In a sixth aspect of the invention, there is provided a saddle comprising the saddle structure defined above. In a seventh aspect of the invention, there is provided a method of assembly of a saddle structure as defined above, the method comprising providing a core tree, mounting thereon one or a plurality of connecting members and connecting the connecting members to a plurality of contact pads. In an eighth aspect of the invention, there is provided a method of assembly of a saddle that includes the saddle structure as defined above, the method comprising assembling a saddle structure as defined above. In a ninth aspect of die invention, there is provided a modular saddle tree comprising an assembly of a plurality of prefabricated component parts, the assembly comprising at least: a seat portion component; and a head portion component, wherein the seat and head portion components are secured relative to one another by elongate longitudinal members and / or by cooperating and / or interlocking projecting elements, to make up a core tree whereby, preferably, a desired longitudinal rigidity is provided to the saddle tree, and which modular saddle tree further comprises: a plurality of contact pads disposed laterally of a central axis of the core tree and disposed along the length of the core tree, for contacting with a horse’s back; and one or more connecting members configured to connect the core tree to the contact pads, wherein the saddle tree structure is configured such that the position and / or angle of the or each of contacting pads may change, relative to the position and / or angle of the core tree. In a tenth aspect of the invention, there is provided a lightweight saddle tree comprising a core tree of injection moulded plastic, the core tree comprising a seat portion and a head portion, wherein the core tree comprises a reinforced peripheral portion extending from the head portion to the seat portion to provide a (preferably desired) longitudinal rigidity and transfer load across the saddle tree; and / or the seat and head portions are formed with a plurality of reinforcing vanes or ribs having a largely longitudinal component of orientation, which serve to increase the longitudinal rigidity of tire part of the saddle tree where they are disposed, the saddle tree further comprising: a plurality of contact pads disposed laterally of a central axis of the core tree and disposed along the length of the core tree, for contacting with a horse’s back; and one or more connecting members configured to connect the core tree to the contact pads, wherein the saddle tree is configured such that the position and / or angle of the or each of contacting pads may change, relative to the position and / or angle of the core tree. In an eleventh aspect of the invention, there is provided a modular saddle tree comprising an assembly of a plurality of prefabricated component parts, the assembly comprising a core tree comprising at least: a seat portion component; and a head portion component; wherein: the saddle tree comprises a reinforced peripheral portion extending from the head portion component to the seat portion component to provide a desired longitudinal rigidity and transfer load across the saddle tree; and / or the seat and head portion components are formed with a plurality of reinforcing vanes or ribs having a largely longitudinal component of orientation, which serve to increase the longitudinal rigidity of the part of the saddle tree where they are disposed, and wherein the modular saddle tree further comprises: a plurality of contact pads disposed laterally of a central axis of the core tree and disposed along the length of the core tree, for contacting with a horse’s back; and one or more connecting members configured to connect the core tree to the contact pads, wherein the saddle tree, when assembled, is configured such that the position and / or angle of the or each of contacting pads may change, relative to the position and / or angle of the core tree. ADVANTAGES OF THE INVENTION The saddle structure, connecting members, contact pads, saddle and method of the invention provide that use of a saddle incorporating the saddle structure results in a more evenly spread load and reduction of pressure points in a horse and a more comfortable ride with improved animal welfare with a reduced risk of causing discomfort or injury to the horse. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1A and IB shows the underside of a conventional prior art saddle; Figure 2A is a top perspective view of an embodiment of the saddle structure of the invention; Figure 2B is a bottom view of the saddle structure of Figure 2A; Figure 2C is a front view of the saddle structure of Figure 2A; Figure 2D is a top perspective view of plate members of the contact pads and connecting members of the saddle structure of Figure 2A; Figure 2E is a top perspective view of plate members of the contact pads and connecting members of the saddle structure of Figure 2A with the middle and rear tree mounts exploded; Figure 2F is a perspective view of a connecting member of the saddle structure of Figure 2A; Figure 2G is a top perspective exploded view of a plate member of the contact pad of the saddle structure of Figure 2A; Figure 2H is a plan view of the plate member shown in Figure 2G; Figure 3 shows an alternative saddle structure with an alternative plate member according to another embodiment of the saddle structure of the invention; Figures 4A, and 4B are side views of a saddle, incorporating the saddle structure of one embodiment of the invention, fitted to a horse; Figure 4C is a view from below of the saddle, incorporating the saddle structure of the embodiment of the invention in Figure 4A; Figures 5A and 5B are perspective view and front views of an embodiment of a cantie component for use in relation to a core tree used in one embodiment of the saddle structure of the invention, in which its lateral mounting projections are disposed at an intermediate configuration; Figures 5C, 5D, 5E and 5F are front views with and without a cover panel of an embodiment of a cantie component for use in relation to a core tree used in one embodiment of the saddle structure of the invention, in which its lateral mounting projections are disposed in retracted and extended configurations; Figure 5G is a perspective exploded view of parts of a cantie component according to an embodiment thereof for use in relation to a core tree used in one embodiment of the saddle structure of the invention; Figures 6A, 6B and 6C are perspective views of an embodiment of a core tree used in one embodiment of the saddle structure of the invention in which a cantie’s lateral mounting projections are disposed in retracted, intermediate and extended configurations; and Figures 7A and 7B are top and bottom views of an embodiment of a seat portion component for use in a core tree used in one embodiment of the saddle structure of the invention; Figure 8A is a top perspective view of a modular core tree for use in one embodiment of the invention; Figure SB is a top perspective view of the modular core tree of Figure 8A with the gullet bar and fixings exploded; Figure 8C is a top perspective view of the modular core tree of Figure 8A less the gullet bar and fixings with the cantie exploded; Figure 8D is a plan view of a separated seat portion and connecting mid-portion of a modular core tree of Figure 8A; Figure 8E is a top perspective view of the modular core tree of Figure 8A absent the gullet bar and fixings, the cantie and the seat portion component and showing the connecting mid-portion component exploded; Figure 8F is a plan view of a separated connecting mid-portion and head portion of a modular core tree of Figure 8A; Figure 9 is a perspective bottom view of a portion of the modular core tree illustrated in Figure 8A; Figure 10A is a side perspective view of a rig used to determine longitudinal rigidity of a core tree; Figures 1 OB is a front perspective view of a rig used to determine torsional rigidity of a core tree; and Figures 11A and 1 IB are images representing the pressure measured against a horse’s back when fitted respectively with a saddle incorporating the saddle structure of the invention (Figure 11A) and a conventional saddle (Figure 1 IB) DETAILED DESCRIPTION OF THE INVENTION The invention concerns a saddle structure comprising a core tree, a plurality of contact pads for contacting with a horse’s back and one or more connecting members for connecting the core tree to the contact pads. It also concerns in related aspects a mounting system for a saddle or saddle structure and a mounting structure and contact pads. Ure core tree may be any suitable saddle tree and may form the basis around which a saddle maker may build a saddle, including webbing and leather cover and seat cushioning. It is not necessary for the saddle tree to have elongate stuffed or padded panels on the underside thereof since the contact between the saddle or saddle structure and the horse will be through the contact pads. A core tree, as used herein, is intended to refer to a saddle tree or a primary body portion thereof, which is intended to form the foundation or structural support member for a saddle. The core tree may be of wood, moulded plastic or any other suitable material. The core tree may be a conventional saddle tree. The core tree should be capable of or adapted to have one or more connecting members mounted to it, preferably to the underside thereof, or may comprise connecting members for connecting to the contact pads. The core tree preferably has a rigid axial section, meaning that a significant medial elongate portion (e.g. the middle two thirds and preferably the full length) of the core tree is substantially rigid, at least in a longitudinal direction and preferably also in a lateral direction. Preferably the entire tree is substantially inflexible. Optionally, the core tree has one or both of a longitudinal rigidity (including a substantial longitudinal rigidity) of from 40 to 100 N / mm, preferably from 50 to 90 N / mm and more preferably from 60 to 80 N / mm and a torsional rigidity of from 90 to 150 N / mm, preferably 100 to 140 N / mm and more preferably from 110 to 130 N / mm. The saddle structure of tire invention has a plurality of contact pads disposed laterally of a central longitudinal axis of the core tree, preferably a plurality disposed laterally to each side of the longitudinal axis of the core tree. A plurality7 of contact pads disposed to each side of the longitudinal axis are preferably disposed along the length of the core tree (preferably in a direction generally parallel with, or in a best fit within 30 degrees of, more preferably within 15 degrees of, the longitudinal axis of the core tree). The contact pads are for contacting with a horse’s back and are preferably the sole load-bearing contacts for the saddle structure with the horse. The saddle structure is configured such that the position and / or angle of the or each of contacting pads may change, relative to the position and / or angle of the core tree, for example in response to the position and extent of load applied to saddle in use. Preferably, there are at least two contact pads disposed laterally to each side of the central axis of the core tree, but there could be any suitable number, such as from two to ten, more preferably up to eight and still more preferably up to five. Optionally, there are four contact pads disposed either side of the axis of the core tree, and preferably at least three contact pads. Where there are two contact pads or three contact pads either side of the central axis of the core tree, they should be arranged from fore to rear. Where there are more than three contact pads, they should generally be arranged from fore to rear, but may be arranged in any suitable pattern, for example in pairs. The arrangement of contact pads on each side of the central axis of the core tree preferably mirrors the arrangement on the opposing side. The contact pads may define any suitable shape (which represent their contact area) and may be irregular or regular in shape, although it is preferred that sharp comers are avoided. If they are irregular shapes, it is preferred that they are configured to cooperate to some extent. For example, the contact pads may independently be quadrangular (e.g. square or rectangular), triangular, pentangular, hexagonal, heptangular, octagonal, circular or oval or other curved and irregular shape. Preferably, at least one of, and preferably each of, the contact pads define a substantially rectangular or square contact area and preferably with rounded-off comers. In any case, it is preferred that the shape of respective adjacent contact pads is such that they have a straight line on the adjacent pad-facing edge, or have cooperating edges, so that the adjacent pads can be placed relatively close to one another. Preferably, each contact pad or the contact area of each contact pad is independently separated from each adjacent contact pad by a distance in the range of from 1 to 10 cm, preferably up to 5 cm, more preferably up to 3.5 cm, still more preferably up to 2.5 cm and most preferably from 1.5 to 2 cm. Preferably, the shape and arrangement of contact pads is such as to define a central longitudinal area between the opposing contact pads on either side of the longitudinal axis of the core tree where there will be no contact with the horse’s back, keeping load away from the spine of the horse, defining an elongate recess or channel for the spine of the horse. This elongate channel may vary' in width along the length of the saddle structure, but preferably has a minimum width of at least 5 cm, preferably at least 10 cm. The contact pads preferably define a cumulative contact (or loadbearing) area of up to 2500 cm2, preferably up to 2250 cm2, preferably at least 500 cm2, more preferably at least 750 cm2, more preferably at least 1000 cm2, and still more preferably at least 1500 cm2. Most preferably, the cumulative contact area is in the range from 1750 cm2 to 2000 cm2. Preferably, the size, shape and configuration of the contact pads is such that, in use, they will be placed into load-bearing contact with the thoracic region of the horse’s back, either side of the spine and to rear of the withers and shoulder blades, so as to avoid particularly sensitive areas of the horse’s back. The contact pads may be of any suitable size in view of the number of pads and the area which they are to cover. Preferably, the contact pads each, independently, have a contact area (or load-bearing area) of at least 200 cm2 and preferably, e.g. where there are a total of six contact pads, a contact area in the range 225 cm2 and 400 cm2. A centre point of the contact area of each contact pad, where there are a total of six contact pads arranged longitudinally along the length of the core tree, is preferably independently disposed laterally from the longitudinal axis of the core tree by a distance in the range from 7 to 15 cm. Preferably, the contact pad comprises a plate member having on one face thereof one or more padding elements or padding material, for contacting with a horse’s back, and being configured for connecting to the connecting member on the other face thereof. The plate member may be a solid generally planar member (although it may not be entirely planar), or a framework structure. Preferably, tire plate member is relatively inflexible, so as to enable a load applied to the plate member to be spread across its area. The plate member may be formed of any suitable material. For example, the plate member may be a metal or a plastic, such as a fibre-reinforced plastic. Preferably, the plate members are, independently, formed of a plastic comprising or formed from a polymer material (a first polymer) that provides resilient properties, such as a polypropylene (or a copolymer of polypropylene) that is optionally: blended with a further polymer (a second and further polymers); provided with a filler; and / or provided with a fibre-reinforcing material in order to impart desirable properties, such as dimensional stability, rigidity, resilience and longevity. For polypropylene, it is desirable to introduce a copolymer, a second polymer in a blend, a fibre-reinforcement or a filler. Any suitable second or further polymers may be provided, which typically are provided in an amount of less than 50% of the total polymer weight, preferably no more than 30%. The secondary polymer may be a cross-linked or cross-linkable polymer material that enables enhanced dimensional stability. Any suitable fibre-reinforcing material may be used in the plastic of the core tree or component thereof, such as carbon fibres, basalt (or other rock-derived) fibres, polymer fibres or glass fibres. Preferably, a fibre loading in the polymer is selected in order to enhance the primary properties of the first polymer (or polymer blend) to achieve the degree of dimensional stability, robustness and workability that is desired. The fibre-reinforcing material may provide fibres orientated in any suitable fashion, but are preferably randomly orientated. Preferably, especially in the case of glass fibres, the fibre-reinforcing material is provided at a loading of 5 to 50% by weight of the resultant composite plastic material, more preferably 10 to 40% and still more preferably 15 to 30%. Most preferably, the fibre loading is about 20 to 25 % by weight. Any suitable filler may be used, such as calcium carbonate, magnesium carbonate or similar, microspheres or any other suitable filler or a combination thereof. The filler may optionally be provided at a loading of up to 50% by weight of the resultant composite plastic material, more preferably 5 to 40% and still more preferably 10 to 30%. Preferably, where a filler and a fibre-reinforcing material are used, the combined content is no more than 60% by weight of the resultant composite plastic material, preferably no more than 50% by weight, still more preferably at least 5% by weight, still more preferably 10 to 40% and still more preferably 15 to 30%. Most preferably, the fibre / filler loading is about 20 to 25 % by weight of the resultant composite plastic. Preferably, the ratio of fibre to filler, where both are present, is up to 20:1 to 1:1, preferably from 10:1 to 5:1. Additives, such as a plasticizer, a lubricant, a hardener or other suitable additives may be used. In a preferred embodiment, the composite plastic material forming the plate members comprises (and more preferably substantially consists of) a glass fibre-reinforced polypropylene or similar polymer or blend thereof with a glass fibre loading of 10-30% by weight of the resulting composite material. Preferably, the plate member has a thickness of up to about 10 mm, preferably up to about 5 mm, and more preferably in the range of 1 to 5 mm. In one embodiment, in which the plate member is a glass fibre-reinforced polypropylene-containing material, the plate member is about 3 mm thick in a medial portion thereof and feathering to about 2 mm thick at a peripheral edge thereof. The plate member may be defined as having a medial portion and a peripheral portion and, at the outer limit thereof, a peripheral edge extending around the entire plate. The plate member may be connected to a connecting member at one or more positions on the upper surface of the plate (i.e. the surface opposing the surface where the padded elements or material are disposed). In one particular embodiment, a plate member may be connected to a connecting member at one position on the plate member at a connecting member mounting point. The connecting member mounting point is preferably disposed medially on the upper surface of the plate member and most preferably centrally. A plate member may have load-spreading features extending from the or each connecting member mounting point. Preferably, the load-spreading features are load spreading ribs and typically they extend radially from the connecting member mounting point. The load-spreading features allow a degree of greater rigidity to be established around the connecting member mounting points, through which any load on the horse will be transferred. In one preferred embodiment where there is a single connecting member mounting point, medially located on the plate member, a plurality of load-spreading ribs extend radially outward from the connecting member mounting point, for example up to twelve, preferably from five to ten, and preferably they taper in size along their radially outward length and preferably extend to about one quarter to three quarters, preferably one third to two thirds of the distance from connecting member mounting point to peripheral edge. Preferably, a peripheral portion of the plate member is divided into a plurality of petals extending peripherally outward from the medial, the petals separated from adjacent petals. Optionally, the petals may be separated by slots that extend inward from the peripheral edge. Slots (or separations) may extend inward from the edge by any suitable amount according to the size of the petals desired, but preferably by about one quarter to one half of the distance from peripheral edge to medial or central point. In embodiments of the plate member where there is one connecting member mounting point, it is preferred that the slots (and thus the petals) converge toward the connecting member mounting point, in which case the slots preferably extend from the peripheral edges of the plates by about one quarter to one half or up to two thirds of the distance from the peripheral edge to the connecting member mounting points. There may be any number of slots and thus petals as are desired, but typically from 3 to 12, preferably 5 to 10. In a particular embodiment in which there is a single, medially located connecting member mounting point and where there is a plurality of radially extending ribs, it is preferred that there is the same number of radially converging slots and that the slots geometrically intercalate with the ribs. In a particularly preferred embodiment, there are 8 radially extending ribs and 8 radially converging and intercalating slots (defining 8 petals). The combination of ribs (or ridges) and slots / petals allows for a thin plate member to be used, which is reinforced and made more rigid close to the connecting member mounting point and provide a stiffness in a direction radially outward from the connecting member mounting point(s) so as to spread the load across the surface / area of the plate members. Petals as provided to enable some degree of local movement and flexibility toward the outer or peripheral portions of the plate members so as to reduce the risk of pressure points occurring at the edges of plate members. To facilitate that flexibility, the thickness of the plate member preferably feathers from medial portion to peripheral edge. This structure of plate member enables the plate member to cover a larger area and have the load spread over that larger area while avoiding pressure points at the edges thereof. The saddle structure of the invention is preferably configured such that each of the contact pads (and thus, where the contact pad comprises a plate, each of the plates) is configured to articulate relative to the core tree and / or the connecting member so as to enable the position and / or angle of each contact pad to change, relative to the position and / or angle of the core tree, typically responsive to the position and extent of load applied to the saddle in use and / or the movement of the horse. Preferably, each such contact pad has an articulating arrangement to which the connecting member is mounted or through which the connecting member is mounted to each contact pad. In embodiments in which the contact pad comprises a plate member, as defined above, there is preferably provided an articulating arrangement linking the plate member to the connecting member or forming part of the plate member and onto which the connecting member may be mounted. The articulating arrangement may be any suitable arrangement that enables the relative movement and, in particular, the relative change of orientation, of the plate member (or contact pad) relative to the core tree (and typically also the connecting member), preferably a change in orientation in vertical direction (tilt) and in a horizontal direction (twist) and more preferably in any and all directions. The articulating arrangement may be the same or different for each contact pad or plate member along the length of the saddle structure, but it is preferred that each pair of opposing contact pads (and plate members) have the same articulating arrangement. The articulating arrangement is selected, independently for each contact pad or opposing pair of contact pads, from one or a combination of: one or an array of resiliently compressible mountings (such as springs, rubber rods, rubber spheres, etc); an arrangement of resiliently deformable load-spreading brackets; and a ball and socket joint. In one embodiment, the articulating arrangement comprises one or an array of resiliently compressible mountings (such as springs, rubber rods, rubber spheres, etc). According to this embodiment, the arrangement may comprise, for example, an array of resiliently compressible mountings disposed between two plate, one being a plate member of a contact pad and the other being a connecting plate fixedly mounted to or a fixed part of a connecting member, whereby the two plates may change in orientation relative to one another and away from a resting orientation according the nature of the load applied to the core tree and the movement of the horse. The resiliently compressible members may be rubber rods or spheres held in sockets in each of the two plates. There may be any number of such compressible members, e.g. four peripheral members and one central member. Optionally, in this latter embodiment, the central member may be stiffer, so as to act as a pivot while the peripheral members may be more deformable. Such an arrangement may also facilitate a degree of co-planar or relative lateral movement of the two plates. A similar arrangement using coiled springs may also be achievable. In another embodiment, the articulating arrangement comprises an arrangement of resiliently deformable load-spreading brackets. In a preferred embodiment, a plurality of, preferably at least two and typically two, sprung shaped material (preferably carbon fibre, but alternatively steel) strips are disposed perpendicular to one another and mounted on a plate member to define a raised overlapping portion, to which a connecting member may be mounted, defining a kind of angular dome. The shape that the sprung material strips are provided / fonned with may be described as half a hexagon - they may comprise distal fixing portions and therebetween angular slopes to a raised central or medial fixing portion parallel with the distal fixing portions and optionally fixed in a slightly laterally compressed state (to make them sprung). The two perpendicular sprung strips define two perpendicular components of resilient adjustability, whereby the plate may be re-orientated in angle in any direction relative to the core tree (and connecting member) depending on changes in die load applied to the core tree or movement of the horse's body and return to the resting position on the return of the load or movement to the starting point. Whilst two sprung strips are described, any number of sprung strips could be used provided they have common overlapping portions to which the connecting member may be mounted. In a further and preferred embodiment, and a ball and socket joint wherein a socket portion is formed or mounted on the plate member and a ball portion is formed or mounted on the connecting member or vice versa and wherein the ball portion and the socket portion are configured to cooperate so as to allow the plate member to change in angle relative to the connecting member and the tree core. In a particular embodiment of the ball and socket joint articulating arrangement, it is preferred that the socket is mounted onto a medial portion of each contact pad plate member and the ball is provided on a stalk extending from a connecting member. In this embodiment, a high-wear bearing (e.g. available from Igus GmbH) may be used as the socket and may be snap-fitted into a mounting element shaped to receive it, which itself may be adhered to a correspondingly shaped mounting point on the plate member surface. The one or more connecting members of the saddle structure are substantially rigid members and fixedly extend from or are fixedly and / or rigidly mounted to the core tree. The connecting members may in one general embodiment comprise lateral downward-angled integral portions of the core tree, which are rigid (i.e. rigidly disposed) relative to the rigid axial portion of the core tree. These lateral downward-angled integral portions are configured to be positioned to connect to contact pads which are to be disposed relative to the central / longitudinal axis of the core tree as described above. Optionally, the laterally downward-angled integral portions are in the form of a single rigid panel on each side of the core tree, which may be mounted to all of the contact pads on the corresponding side of the core tree. Alternatively, the laterally downward angled integral portions are discrete projections extending from a body of the core tree and configured to mount to one or a proportion of the contact pads on the corresponding side of the core tree. Optionally, there is one or more than one such discrete projections. In another general, and preferred, embodiment, there may be a plurality of discrete connecting members, each configured to be mounted to a single contact pad on one side of the core tree. Preferably, a connecting member (and optionally each connecting member) comprises a rigid arm extending from the core tree and configured for mounting to a contact pad (or plate member thereof). The rigid arm may be formed of any suitable material including metal, plastic (including fibre-reinforced plastic) or carbon fibre. Preferably, each rigid arm is formed of carbon fibre or steel. Each connecting member, optionally in the form of a rigid arm, may be a discrete element mounted to and extending from the core tree to connect to a single contact pad on one side of the core tree. Alternatively, and preferably, two opposing connecting members, one on each side of the core tree for connecting to two opposing contact pads, are formed of a single bracket element which is mounted in a central or medial portion and extends in both lateral directions to form two opposing connecting members (in the form of rigid arms). In this case, it is preferred that the bracket element comprises a shaped elongate member (formed of a single length of rigid material) having a central tree-mounting portion that is typically planar and configured for mounting to, for example, an underside of the core tree, and two opposing downward-angled portions having distal end portions for mounting to the contact pad (and which, in one embodiment, have balls disposed at a distal plate-mounting portion for cooperation with a corresponding socket on the plate member of the contact pad). Optionally, the plurality of connecting members includes more than one type of connecting member selected from the aforementioned integral discrete projections, discrete rigid arm elements forming a single connecting member and bracket elements forming two opposing connecting members. In one particular embodiment, which is preferred, in which the saddle structure comprise three contact pads disposed to each side of the central axis of the core tree, the pairs of opposing rear and middle contact pads are connected to the core tree by a rear bracket serving as the connecting members for the two opposing rear contact pads and a middle bracket serving as the connecting members for the two opposing middle contact pads, while the fore contact pads are mounted by two discrete rigid arm elements mounted on an integral projection (which also serves as the gullet portion of the headplate to which is mounted a gullet bar) of tire core tree. In each case, the connecting member preferably mounts to the contact pad via an articulating arrangement, such as those defined above, and preferably by way of a ball and socket joint. In embodiments in which a rigid arm, as connecting member, is mounted to the core tree, whether as a discrete rigid arm or as part of a bracket element providing two connecting members, it is preferred that the rigid arms are mounted to the core tree via a bracket mounting point formed on an underside of the core tree. A bracket element may be mounted to the bracket mounting point using a discrete tree mount, which may be adhered or otherwise affixed to specific formations at the bracket mounting point and the tree-mounting portions of the bracket element may be affixed, e.g. using screws or other fixings, to the tree mount. The saddle structure is described above (and below) in terms of embodiments and features that are applicable to particular aspects of the invention, but it should be noted that these embodiments and features should be considered as applicable directly to other aspects of invention described herein where the context allows. In a preferred embodiment of the invention, which may be applicable to any of the aforementioned saddle structures, the core tree may be as further described in the embodiments set out below. In one general embodiment, the core tree is a modular core tree comprising an assembly of a plurality of prefabricated component parts, the assembly comprising at least: a seat portion component; and a head portion component, wherein the seat and head portion components are secured relative to one another by elongate longitudinal members, whereby a desired longitudinal rigidity is provided to the core tree. In a second general embodiment, the core tree comprises a reinforced peripheral portion extending from the head portion component to the seat portion component to provide a desired longitudinal rigidity and transfer load across the core tree; and / or the seat and head portion components are formed with a plurality of reinforcing vanes or ribs having a largely longitudinal component of orientation, which serve to increase the longitudinal rigidity of the part of the core tree where they are disposed. In a third general embodiment, the core tree is a lightweight core tree of injection-moulded plastic, the core tree comprising a seat portion and a head portion, wherein the core tree comprises a reinforced peripheral portion extending from the head portion to the seat portion to provide a desired longitudinal rigidity and transfer load across the core tree; and / or the seat and head portions are formed with a plurality of reinforcing vanes or ribs having a largely longitudinal component of orientation, which serve to increase the longitudinal rigidity of the part of the core tree where they are disposed. Optionally, the core tree may be said to have a mid-portion, which may be the narrowest point of the core tree. The core tree according to this aspect may be formed of a single injection-moulded part comprising at least the head portion and the seat portion, i.e. extending from a headplate to a rear edge of the seat portion. Optionally, the core tree according to this aspect may be provided with a cantie that is an injection-moulded part, which is optionally injection moulded in a single, unitary, part with the head portion and seat portion. Preferably, however, the cantie is provided as a discrete member, which may be of a more rigid material than the core tree, such as wood or plywood, and affixed to the rear edge of the seat portion. Optionally, the cantie is a discrete member made of injection moulded plastic in multiple parts and may be an adjustable cantie component as described elsewhere herein. Preferably, a discrete gullet bar may be provided and fitted to the underside of a headplate of the head portion. In a fourth general embodiment, the core tree is a modular core tree that comprises an assembly of a plurality of prefabricated component parts, the assembly comprising at least: a seat portion component selected to have a desired seat portion length, width and configuration; a cantie portion component selected to have a desired width and cantie angle and extent of projection (and optionally being an adjustable cantie component as described herein), the cantie portion component being affixed to a rear part of the seat portion component; a head portion component configured to receive a gullet bar of a range of curvatures; and a gullet bar fixed to the head portion component, wherein the components parts may be selected according to horse-fit and rider preference requirements to provide a specific core tree onto which to build a saddle. A modular core tree, when incorporated into the present saddle structure, may be used as the basis upon which to make a saddle, by traditional or more contemporary means, and provides an opportunity to build a bespoke saddle having desired dimensions for fitting both horse and rider or to establish a manufacturing line capable of rapid production of a wide variety of saddle tree variants, without the need to keep large amounts of stock or to manufacture the saddle tree upon request, and to provide desired characteristics of weight and flexibility that provide a comfortable saddle for horse and rider, while maintaining a robust support. By elongate longitudinal members, it is meant elongate members that are disposed or configured for disposal generally along the length of the core tree (rear to fore). There are various configurations by which a modular core tree can be assembled using such elongate longitudinal members. Typically, the seat and head portion components are secured relative to one another by cooperating elongate longitudinal members. For example, the seat and head portion components may be mounted together (e.g. so that the edges of the seat and head portion components abut) by one or more discrete elongate longitudinal members (or other discrete mounting bracket member), optionally received within recesses in an upper surface or more typically a lower surface of the seat and head portion components. Alternatively, or additionally, such elongate longitudinal members (or mounting members) may form part of one or other of the seat portion component or the head portion component and preferably be received by corresponding recesses in the other component. Optionally, the elongate longitudinal members may have a full depth, by which it is meant form upper and lower surfaces of the resulting assembled core tree and have laterally and longitudinally projecting ribs or flanges and where the elongate longitudinal member are received in channels (extending through the fall depth of a receiving member) with partial depth recesses (defining cooperating flanges) corresponding with the lateral ribs / flanges of the elongate member. Preferably, the seat and head portion components are secured relative to one another by cooperating elongate longitudinal members. Preferably, the modular core tree comprises a connecting midportion component which is secured to each of the seat portion component and the head portion component and preferably serves to secure the head and seat portion components relative to one another. While the connecting mid-portion component may optionally be unseen (i.e. have no upper surface, acting simply as a bracket), preferably, the connecting mid-portion component has a core element, defining front and back edges abutting corresponding edges of the head and seat portions and defines at least part of an upper surface of the resulting assembled core tree. Preferably, the connecting mid-portion component extends the foil width of the assembled core tree. Preferably, the connecting mid-portion component is secured to the seat portion component and the head portion component longitudinally extending elongate members projecting therefrom (e.g. from the core element) and / or from the seat portion component and / or from the head portion component, which are preferably cooperatively received in corresponding recesses and / or channels in respective other of the connecting mid-portion, head portion and seat portion components. Additionally, or alternatively, the mid-portion component is secured to each of the seat portion component and the head portion component by overlapping and cooperating forward and backward projecting features or flanges which form upper and lower parts of that overlapping portion of the core tree when assembled. Preferably, a cooperating pair of forward and backward projecting features, one say form the seat portion component (for example an upper forwarding projecting feature) and one from the connecting mid-portion component (for example, a lower rearward projecting feature) cooperate to form a joint in which foe terminal edges of the upper and lower projecting features meet edges of foe corresponding surfaces of foe other component defining a cooperating recess so that when assembled foe upper surfaces of the seat portion component and the connecting mid-portion component define a continuous uninterrupted surface, akin to a lap-joint. A similar such lap-joint arrangement may preferably be provided between the head portion component and the connecting mid-portion component. In one embodiment, the elongate members cooperate with recesses and / or channels provided in the respective seat portion, connecting mid-portion and head portion components. In one particular preferred embodiment, foe connecting midportion component comprises a core element and projecting therefrom two forward extending elongate members configured to be disposed peripherally, either side of a central longitudinal core tree axis, and wherein the head portion component is provided with recesses and / or channels for cooperative engagement with the forward extending elongate members of the connecting mid-portion component. Alternatively, two rearward extending elongate members extending from the head portion component are disposed peripherally, either side of a central longitudinal core tree axis, and the connecting mid-portion component is provided with recesses and / or channels for cooperating with the rearward extending elongate members. In another particular, preferred, embodiment, the seat portion component has projecting therefrom two forward extending elongate members configured to be disposed peripherally, either side of a central longitudinal axis, and wherein the connecting mid-portion component is provided with recesses and / or channels for cooperative engagement with the forward extending elongate members of the seat portion component. Alternatively, two rearward extending elongate members extending from the mid-portion component are disposed peripherally, either side of a central longitudinal core tree axis, and the seat portion component is provided with recesses and / or channels for cooperating with the rearward extending elongate members. In one embodiment of the assembly, a seat portion component, a connecting mid-portion component and a head portion component are secured together at least by two forward projecting peripherally disposed members on the connecting mid-portion component received in a corresponding recess on the head portion component and by two rearward projecting peripherally disposed members on the connecting mid-portion component received in a corresponding recess on the seat portion component, the connecting mid-portion component preferably forming an H-shaped member. In another, preferred, embodiment of the assembly, a seat portion component, a connecting mid-portion component and a head portion component are secured together at least by two forward projecting peripherally disposed members on the connecting mid-portion component received in a corresponding recess on the head portion component and the at least two forward projecting peripherally disposed members on the seat portion component received in a corresponding recess on the connecting mid-portion component. It is preferred that the projecting elongate longitudinal members and the corresponding recesses provided a significant degree of overlap between the cooperating components. For example, it is preferred that forward extending elongate members of the connecting mid-portion component (or seat portion component, in the absence of a mid-portion component, for example) extend into and overlap with the head portion component by an amount of from one-quarter to three-quarters of the longitudinal extent of the head portion component (the degree of overlap of the head portion component with the mid-portion component, or seat portion component, being of that nature also when the projection is from the head portion into recesses formed in the connecting mid-portion and / or seat portion component). The overlap between the head portion component and the connecting mid-portion component (or, in its absence, the seat portion component) may be an area of at least 10 cm2, preferably at least 25 cm2 and more preferably at least 40 cm2, still more preferably at least 50 cm2 and optionally at least 75 cm2, and optionally up to 150 cm2. Furthermore, for example, it is preferred that elongate longitudinal members that work to secure the connecting mid-portion component (or head portion component, in the absence of a mid-portion component, for example) and the seat portion component overlap by an amount of from one-quarter to three-quarters of the longitudinal extent of the seat portion component (the degree of overlap of the seat portion component with the midportion component, or head portion component, being of that nature whether the projection is from the seat portion into recesses formed in the connecting mid-portion and / or head portion component or vice versa). The overlap between the seat portion component and the connecting mid-portion component (or, in its absence, the head portion component) may be an area of at least 10 cm2, preferably at least 25 cm2 and more preferably at least 40 cm2, still more preferably at least 50 cm2 and optionally at least 75 cm2, and typically up to 150 cm2. Ulis extensive overlap of projecting members of the respective components serves to ensure the joint is robust and serves to stiffen the core tree along the areas of overlap. Preferably, upper and lower projecting features (or members) from adjacent components of the modular core tree, which cooperate to form an overlapping portion and robust joint, comprise any elongate projecting members. Preferably, such upper and lower projecting features extend the frill width of the core tree. The minimum overlap of such overlapping upper and lower projecting features may, for example, be 15 mm, preferably at least 20 mm and, optionally, at least 25 or 30 mm. The overlapping elements of the respective components of the modular core tree may be fixed together by any suitable means, but are preferably fixed by threaded bolts or screws that secure into receiving threads formed in the inner surface of the respective recesses. Preferably, according to any of the aspects or embodiments herein, the core tree comprises a reinforced peripheral portion extending from the head portion component to the seat portion component to provide a desired longitudinal rigidity and transfer load along the core tree. The reinforced peripheral portion preferably comprises the aforementioned overlapping elongate longitudinal member and cooperating recessed portions of neighbouring components, preferably both of the peripherally disposed elongate longitudinal members connecting the seat portion component to the connecting mid-portion component and the peripherally disposed elongate longitudinal members connecting the head portion component to the connecting mid-portion component, which are preferably longitudinally aligned or generally aligned front to back. The overlapping areas of elongate longitudinal members and cooperating recesses can be said to be reinforced peripheral portions or reinforced zones. Preferably said reinforced peripheral portions are proximal, preferably adjacent or adjoining, front to back, introducing a continuous longitudinal stiffness along the length of the modular core tree whereby load can be effectively transferred from flank portions of the head portion component or proximal thereto along the length of the reinforced elongate mid-head and reinforced elongate seat-mid peripheral portions and therefore along the outside edge of the core tree. Thereby load may be spread along the outside edge of the core tree. The reinforced peripheral portion extending from the head portion component to the seat portion component to provide a desired degree of stiffness and to facilitate load transfer may be of any suitable width. Preferably, the reinforced peripheral portion is from the outer edge of the core tree or proximal thereto and has a width of at least 2 cm. preferably from 3 to 5 cm along at least two-thirds of its length. Preferably, according to any of the aspects or embodiments herein, the core tree comprises at least seat and head portion components (and optionally a connecting mid-portion component) that are formed with a plurality of reinforcing vanes or ribs having a largely longitudinal component of orientation, which serve to increase the longitudinal rigidity of the part of the core tree where they are disposed. In one embodiment, it is these areas of reinforcing vanes or ribs that serve to establish the reinforced peripheral portion extending from the head portion component to the seat portion component to provide the desired longitudinal rigidity and transfer load along the core tree. In one embodiment, the substantially longitudinally orientated reinforcing vanes are disposed primarily to the rear of the seat portion component and to the fore of the head portion component. Optionally, the core tree comprises a medial portion which is characterized by having a plurality of substantially transverse orientated reinforcing vanes, the medial portion optionally comprising a fore portion of the seat portion component, a rear portion of the head portion component and / or a connecting mid-portion component. The head portion component preferably comprises a headplate defining an arcuate form at the foremost part of the head portion, straight or curved opposing sides leading to two opposing peripheral flank portions, typically flared outward relative to the sides of the headplate. The headplate is typically configured to receive and is mounted in relation to a gullet bar, being a rigid arcuate bar member typically having an arcuate central portion of defined curvature and two opposing side bar portions disposed at a pre-defined angle and opposing peripheral flank members, flared outward and cooperating with the peripheral flank portions of the headplate. The shape and angle of the gullet bar (and the headplate) are typically selected to fit a particular horse. The gullet bar is typically secured to the underside of the headplate by any suitable fixing means. As used herein, the term ‘headplate’ is that fore portion of the head portion of a core tree that, as mentioned above, is configured to receive and is mounted m relation to a gullet bar and defines an arcuate central portion with opposing side bar portions extending downwardly therefrom. The headplate is that part of the core tree upon which a pommel is formed on a saddle. The headplate may also be referred to as the forks. The gullet bar is a rigid element and formed of any suitable rigid material, in principle, although typically of metal such as steel. The head portion, with gullet bar in position in situ with the headplate, preferably defines a headplate or gullet bar angle of 70 to 120°, preferably 75 to 110°. For example, there may be provided multiple gullet bars from which to select a gullet bar of different angles (and optionally having a range of arm lengths), such as 75°, 85°, 95°, 100°, 110°. Similarly, there may be provided a range of head portion components of different headplate angles, for receiving a gullet bar, the headplate angle being in the range of 70 to 120°, preferably 75 to 110°. For example, there may be provided multiple head portion components from which to select a headplate defining a gullet bar receiving angle of 75°, 85°, 95°, 100° or 110°. Preferably, however, the head portion is configured to have some flexibility in its headplate whereby the angle can be adjusted across a range of angles in order to fix to a range of gullet bar angles and sizes. For example, the head portion may be configured to have a headplate that can flex to receive a gullet bar across the full range of available gullet bars (e.g. 70 to 110°) or the head portion may be selected from say two head portion components, each configured to flex across at least part of the range of angles of gullet bars, e.g. one may flex from 70 to 95° while another may flex from 85 to 110°. Stirrup bars are preferably provided on the head portion component, on each side of the head portion, preferably mounted at or proximal to the flank portion and a peripheral edge of the head portion. Ideally, the stirrup bars will be mounted and fixed in at least two locations for robustness. The stirrup bars are often the point of greatest load on the saddle, and this is transferred to the horse via the areas proximal to the stirrup bars and notably the flank portions mentioned above. Thus, load transfer is desirable from the flank portions longitudinally along the outer sides of the core tree, to spread the load on the stirrup bars more evenly along the points of contact of the saddle. The aforementioned longitudinal stiffness and, in particular, longitudinally aligned elongate stiffening portions (members) that are provided along the peripheral edges of the core tree serve to achieve this. Front connecting member for connecting to plate members (or contact pads) may advantageously be mounted on the flank portions, optionally in a mounting arrangement cooperating with the mounting arrangement for the stirrup bars. The stirrup bars are typically formed of a rigid and strong material and are typically stainless steel, brass, aluminium bronze or similar. Preferably, the modular core tree further comprises a cantie portion provided for by a cantie component. Tire cantie component may be selected to have a desired width and cantie angle and extent of projection, the cantie portion being affixed to a rear part of die seat portion (e.g. to mounting parts) and optionally via a seat-mounting projection. This may be selected to suit riding style, purpose and fit. The cantie may be mounted to a rear edge of the seat portion component with appropriate fixings, e.g. fixing screws that extend through cantie mounting apertures recessed along the rear edge of the seat portion component to fix into a lower flange (or seat-mounting projection) of the cantie component. The cantie is typically formed of a more rigid material than the seat portion. Suitably, the cantie may be formed of an injection-moulded plastic (optionally a stiffened or reinforced plastic) and may incorporate a series of ribs or vanes for strength (e.g. radiating from the fixing locations of the cantie) or the cantie may be made of plywood. Optionally, the cantie may be an adjustable cantie component as is described in more detail below. The core tree may further comprise points, which may be mounted to a fore part of the head portion component. Tire points may be formed of any suitable material. For example, the points may be synthetic (e.g. moulded or injection-moulded plastic) but may alternatively be of wood or a composite wood material. The core tree should preferably be lightweight, have sufficient longitudinal and torsional rigidity (i.e. to provide a desired flexibility’ for both working and to move with the resulting saddle and the horse while sufficient rigidity to maintain its fonn, maintain balance and support and enable effective load transfer along the length of the saddle), be readily manufacturable and be workable (e.g. to attach fixings, to drill) and to be robust to handling. The core tree or components thereof may be formed of any suitable material which provides the desired properties of rigidity, support and workability. Preferably, the core tree or components thereof, especially the seat portion component, the head portion and any connecting mid-portion component (which may be formed of the same or different materials), but also optionally the cantie component (e.g. an adjustable cantie component), are formed of a plastic material and more preferably are injection-moulded. Preferably, the core tree or components thereof, independently, are formed of a plastic comprising or formed from a polymer material (a first polymer) that provides good workability and resilient properties, such as a polypropylene (or a copolymer of polypropylene) that is optionally: blended with a further polymer (a second and further polymers); provided with a filler; and / or provided with a fibre-reinforcing material in order to impart desirable properties, such as dimensional stability, rigidity-, resilience and longevity. In particular, polypropylene, while providing desirable properties of resilience, flexibility and yvorkability, has a tendency to creep under consistent load. Therefore, for polypropylene (and any other polymer with advantageous properties but a tendency for such creep) it is desirable to introduce a copolymer, a second polymer in a blend, a fibre-reinforcement or a filler to improve the properties. Any suitable second or further polymers may be provided, which typically are provided in an amount of less than 50% of the total polymer yveight, preferably no more than 30%. The secondary polymer may be a cross-linked or cross-linkable polymer material that enables enhanced dimensional stability. Any suitable fibre-reinforcing material may be used in the plastic of the core tree or component thereof, such as carbon fibres, basalt (or other rock- derived) fibres, polymer fibres or glass fibres. Preferably, a fibre loading in the polymer is selected in order to enhance the primary properties of the first polymer (or polymer blend) to achieve the degree of dimensional stability, robustness and workability that is desired. Hie fibre-reinforcing material may provide fibres orientated in any suitable fashion, but are preferably randomly orientated. Preferably, especially in the case of glass fibres, the fibre-reinforcing material is provided at a loading of 5 to 50% by weight of the resultant composite plastic material, more preferably 10 to 40% and still more preferably 15 to 30%. Most preferably, the fibre loading is about 20 to 25 % by weight. Any suitable filler may be used, such as calcium carbonate, magnesium carbonate or similar, microspheres or any other suitable filler or a combination thereof. The filler may optionally be provided at a loading of up to 50% by weight of the resultant composite plastic material, more preferably 5 to 40% and still more preferably 10 to 30%. Preferably, where a filler and a fibre-reinforcing material are used, the combined content is no more than 60% by weight of the resultant composite plastic material, preferably no more than 50% by weight, still more preferably at least 5% by weight, still more preferably 10 to 40% and still more preferably 15 to 30%. Most preferably, the fibre / filler loading is about 20 to 25 % by weight of the resultant composite plastic. Preferably, the ratio of fibre to filler, where both are present, is upto 20:1 to 1:1, preferably from 10:1 to 5:1. Additives, such as a plasticizer, a lubricant, a hardener or other suitable additives may be used. In a preferred embodiment, the composite plastic material forming the core tree or components thereof comprises (and more preferably substantially consists of) a glass fibre-reinforced polypropylene or similar polymer or blend thereof with a glass fibre loading of 10-30% by weight of the resulting composite material. A particular advantage of the described materials, particularly the provision of polymer (especially polypropylene or a copolymer or blend thereof) with filler or fibre-reinforcement, is that makes the core tree (or selected components thereof) more dimensionally stable, and notably so under load, so that load creep is not a significant problem. Furthermore, such materials enable the core tree to be workable, thereby allowing a saddle maker to conduct the construction of the saddle, even using more traditional techniques (which usually make use of a wooden core tree), including the use of staples, screws, nails and other fixings that can be received in the core tree (and components thereof) of preferred embodiments, and hold, without significant issues with splintering. Similarly, such materials can enable the use of a drill and the application of fixings, recessed threads or mounting posts in drilled holes. The components of the core tree may be manufactured of different materials in order to impart particular properties, although it is preferred that they have similar dimensional stabilities. For example, it may be desirable for the seat component and / or any connecting mid-portion component to be formed of a material that is stiffer than that of the head portion component, since it may be desired to have more flexibility and resilience in and about the headplate, for example. Further, it may be desired to have a less brittle and more workable material for the head portion component, where certain additional components (such as the stirrup bars and the gullet bar) are affixed. Thus, for example, it may be desirable for the material used for the head portion component to be formed of a composite material containing a fibre-reinforcing material loading of, say from 2 to 10% less, in terms of the total loading of fibre reinforcing material by weight of resultant composite material, than that of the connecting mid-portion or seat components. In order to maintain a lightweight core tree while maintaining structural integrity and sufficient longitudinal rigidity, the core tree is preferably formed of a thin plastic material, in the form of panel-like elements, of from 1.5 to 4 mm thickness, preferably 2 to 3 mm and more preferably up to 2.5 mm thick. Vanes or ribs may be incorporated to provide thicker portions at the vanes or ribs, e.g. up to 10 mm, preferably up to 5 mm, and more preferably from 3.5 to 4.5 mm. Preferably, vanes project from the panel-like elements by an amount of up to 5 mm, preferably 1 to 4 mm, e.g. 2 to 3 mm. Vane width may be from 0.5 to 3 mm, preferably from 1.5 to 2.5 mm. Vanes may be provided to provide structural integrity, especially on larger elements and provide stiffness in particular orientations (e.g. by orientating vanes longitudinally or with a longitudinal component). Ribs may be provided for additional rigidity, especially in the vicinity of fixings or fixing mounts or areas of particular structural stress or load transfer. Ribs may be of a similar degree of projection as that defined for vanes above (e.g. 1 to 4 mm), preferably about 2.5 mm (e.g. 2 to 3 mm). Ribs may be of any suitable width according to requirements (e.g. from 1 to 8 mm wide and optionally 4 to 6 mm). The overall dimensions of the core tree may be defined according to the particular requirements of the user (and may be achieved by appropriate selection of component parts), but preferably comprises a length of 40 to 50 cm, more preferably from 42 to 48 cm (measured from the fore edge of the head plate to the rear edge of the cantie). Preferably, the core tree comprises a width at the twist (i.e. its narrowest point - typically the mid-point, e.g. across the mid-portion, defined by the connecting mid-portion component) of 110 to 160 mm, preferably 120 to 150 mm. For example, component parts may be selected which provide a twist width of 120 mm, 125 mm, 130 mm, 140 mm and 150 mm (or any combination of choice). Longitudinal stiffness may be provided, as discussed above, by provision of a reinforced peripheral portion and / or longitudinally disposed elongate members, which themselves may be reinforced. Reinforcement may be provided simply by greater thickness of material in the peripheral portion or elongate members, or by providing a reinforcing insert (e.g. a metal or plastic insert element that can be fixed onto the peripheral portion or elongate members), by providing ribs or vanes as described above at the peripheral portion or elongate members, preferably with a larger component of longitudinal orientation, or by provision of a reinforcing panel member. A reinforcing panel member, for example, may be a further discrete, typically plastic injection-moulded, element of the same or different material to the core tree components (e.g. it may be formed of a stiffer material) which is ty pically thin and light weight and optionally provided with ribs or vanes (e.g. on an insider thereof) for stiffening in the desired orientation and which is configured, with the core tree component, for cooperation. Typically, the reinforcing panel member may be fixed to the core tree component with a plurality of fixings (e.g. screws or threaded bolts via aperture in the panel members and threaded apertures in the core tree component). For example, in a preferred embodiment, the seat component comprises a reinforcing panel member on each peripheral portion thereof, preferably elongate from proximal to the rear edge forward (e.g. to a forward projecting elongate member or encompassing a forward projecting elongate member). Furthermore, longitudinal stiffness can be provided by the provision of longitudinally disposed vanes or ribs (or vanes or ribs having a longitudinal component and preferably having a larger component of their orientation being longitudinal). For example, larger portions of panel elements of the core tree or components thereof may be provided with vanes to improve their integrity and longitudinal stiffness. For example, the central and rear portion of a seat portion component may be provided with a plurality of vanes with a generally longitudinal orientation (e.g. with a separation of 1 to 4 cm). Similarly, the head portion from the rear edge thereof to the headplate, typically about the central portion, may be provided with vanes (especially toward the fore or headplate) which are preferably separated by 1 to 4 cm, to provide longitudinal stiffness and structural integrity and preferably are flared from rear to fore to allow some flexibility of the headplate about its longitudinal axis. Preferably, the core tree has a desired degree of torsional stiffness (i.e. relating to twisting about a longitudinal axis of the core tree). It is desired to have a little flexibility to facilitate some degree of movement of the core tree (and the resulting saddle) with the horse as it moves, while providing a desirable degree of support for the saddle and for the rider. Torsional stiffness may be achieved, for example, by peripheral and more particularly bridged peripheral stiffening or reinforcement. In particular, it is preferred that a degree of torsional stiffness is provided by a combination of peripheral reinforcement portions and / or longitudinal elongate members that are peripherally disposed on the core tree in combination with lateral or transverse reinforced portions, linking the peripheral reinforcement portions to form a box or rectangular arrangement of reinforcement. Preferably, there are at least two and preferably three lateral or transverse reinforcement portions, to provide an anchored box or rectangular arrangement of reinforcement. In one particular embodiment, peripheral reinforcement portions (e.g. including longitudinal elongate members) are linked by a mid-portion lateral reinforcement (e.g. provided by a connecting mid-portion component) and a rear lateral reinforcement (e.g. provided by a reinforcing member at a rear edge of the seat portion and / or, preferably a rigid cantie component disposed across the width of the seat portion component at its rear edge). This combination, in addition (optionally) to a degree of rigidity and structural integrity across the body of the core tree and, in particular, the seat portion by curved vanes, serves to introduce a degree of torsional stiffness to the core tree. Preferably, according to this embodiment, the rectangular arrangement of reinforcement may be further anchored by a further lateral reinforcement member which is preferably provided by the head portion and, preferably, tire headplate when secured to a rigid arcuate gullet bar. Thus, the rigid gullet bar anchors, via peripheral reinforced portions (e.g. overlapping portions of the connecting mid-portion component and the head portion), the rectangular reinforcement arrangement of the cantie, mid-portion transverse reinforcement and the peripheral reinforcement connecting them. Thus, additional torsional stiffness can be achieved. Preferably, the core tree has a longitudinal rigidity of from 40 to 100 N / mm, preferably from 50 to 90 N / mm and more preferably from 60 to 80 N / mm. Preferably, the core tree has a torsional rigidity of from 90 to 150 N / mm, preferably 100 to 140 N / mm and more preferably from 110 to 130 N / mm. Longitudinal and torsional rigidity may be measured by any suitable means. Preferably, however, longitudinal rigidity is measured longitudinally between the flank portions and gullet bar at one end of the core tree and proximal to the rear edge of the core tree at the other end. Thus, a rig may be used to support the core tree at these two points and a weight applied to the middle, or close to the middle, of the core tree (e.g. by suspending a weight from a mid-point of the core tree, such as a length of a flexible member such as a length of webbing disposed over the core tree with weights attached to each end, or to both ends together). The weight may be increased incrementally whilst the deflection of the core tree may be measured. Most typically, tire deflection to the core tree may be measured by positioning strain gauges against the underside of the core tree at various positions along the central axis of the core tree, although any suitable means may be used. Preferably, torsional rigidity is determined by securing the head of the core tree in a fixed position and measuring the relative deflection at one side of the core tree upon the application of a weight to one side of tine core tree. The rear of the core tree may be supported by a pivotally mounted cross member configured to support two peripheral portions of the rear (e.g. seat portion) of the core tree. The core tree may be clamped in position on the cross member. A weight may then be applied to one side of the core tree, e.g. by suspending a weight on one end of the pivotally mounted cross member. Strain gauges associated with each side of the rear portion of the core tree (e.g. mounted relative to opposing ends of the pivotally mounted cross member) may be used to measure the deflection caused by the weight. The amount of weight may be increased incrementally and the relative deflection of one side relative to the other side (i.e. the degree of twist or torsional deflection) may be measured and a value of torsional rigidity determined therefrom. Thus, a core tree can be provided that has a desired degree of longitudinal rigidity and, preferably, with a cantie-free seat portion that has a degree of torsional and / or lateral flexibility that enables the final shape of the core tree to be adapted according to horse fit / rider preference, by shaping a rear portion of the core tree to a desired profile shape and fitting thereto a cantie with a desired (selected) mounting interface shape (or curve) to hold the shaped seat portion in position / defme its shape and to introduce the required torsional and transverse rigidity. There is further provided, as another aspect, a kit of parts for use in assembly of the modular core trees defined above. Hie kit of parts preferably comprises at least a head portion component and a seat portion component and, preferably, a connecting mid-portion component. Preferably, the kit of parts comprises a cantie, such as an adjustable cantie component as described below. Preferably, the kit of parts comprises a gullet bar. Preferably, the kit of parts comprises stirrup bars. Preferably, the core tree (including a cantie, gullet bar and stirrup bars) has a weight in the range of from 1.5 kg to 2.75 kg, preferably from 1.7 kg to 2.5 kg. In one embodiment, the core tree is adjustable to fit different horses requiring a range of gullet bar angles, wherein the core tree has an adjustable head portion comprises a headplate configured for receiving, adapting its shape to and mounting to a gullet bar of any of a range of gullet bar angles, and a means for accessing a gullet bar mounted at the underside of the headplate of the core tree, for detaching and removing the gullet bar and of inserting and affixing an alternative gullet bar of different gullet bar angle. For example, a saddle including the core tree may be provided with a releasable flap or a pocket accessible from beneath the saddle which may provide access to the gullet bar. The gullet bar may be secured to the underside of the headplate by any suitable fixing means, but is preferably secured by means accessible via a flap or pocket in a saddle containing the head portion component. Preferably, the head portion is adjustable so that the angle defined by the headplate can be adjusted to accommodate a gullet bar with a head plate or gullet bar angle of from 70 to 120° or any sub-range there, such as 75 to 110° or, for example, from 75 to 90° or 85 to 110°. Preferably, the head portion is adjustable so as to accommodate a gullet bar with a gullet bar angle at least of 5° range (e.g. within the range 70 to 120°), preferably at least 10°, more preferably at least 20°, still more preferably at least 30° range. Optionally, the head portion may be adjustable so that the headplate may define a gullet bar angle that varies by up to 45°. Optionally, the core tree comprises an adjustable cantie component for mounting to a seat portion of the core tree. The adjustable cantie component preferably comprises a cantie body and extending therefrom a seat-mounting projection or interface configured for mounting to a corresponding mounting part of the seat portion. The seatmounting projection or interface comprise two opposing lateral mounting projections. The adjustable cantie component is preferably configured such that the relative angle of the two opposing lateral mounting projections may be adjusted between a first mounting angle and a second mounting angle. Preferably, adjustment of the relative angle of the opposing lateral mounting projections changes the shape or configuration (e.g. curve) of the seatmounting projection (or interface). (“Shape” will be used to represent shape, configuration or curve hereinafter). The seat-mounting projection (or interface) of the adjustable cantie component may take any suitable shape and may be adjusted to another shape as desired. For example, the shape of the seat-mounting projection (or interface) of the adjustable cantie component may an approximately straight line (which may represent the relative angle of the opposing lateral mounting projections being 180°), or it may define a convex shape or curve (e.g. which curves or angles up from an inner to outer direction) (which may represent the relative angle of the opposing lateral mounting projections being greater than 180°) or it may define a concave shape or curve (e.g. which curves or angles down from an inner to outer direction) (which may represent the relative angle of the opposing lateral mounting projections being less than 180°). In one embodiment, the relative angle of the opposing lateral mounting projections may be adjustable by up to 30°, which corresponds to each lateral mounting projection being adjustable by up to 15° relative to the cantie body or to its starting position. Preferably, the relative angle of the opposing lateral mounting projections may be adjustable by up to 20°, more preferably up to 15°. A particularly useful configuration allows the relative angle of the opposing lateral mounting projections to be adjustable by up to 10°, which corresponds to each lateral mounting projection being adjustable by up to 5° relative to the cantie body or to its starting position. Preferably, the relative angle of the opposing lateral mounting projections is adjustable about an intermediate (e.g. half-way) position in which the shape of the seat-mounting projection is a straight line (e.g. as defined by the arrangement of fixing apertures along its length). In any case, it is preferred that it is adjustable about an intermediate position in which the shape of the seatmounting projection (e.g. as defined by the arrangement of fixing means / apertures along its length) corresponds to the resting configuration of the seat portion to which it is to be mounted (i.e. in which the adjustable cantie can be mounted to the seat portion without manipulating the shape, e.g. the profile, of the seat portion). In a preferred embodiment, the adjustable cantie component comprises a body portion and at least two opposing lateral mounting projections that are moveable relative to the body portion (and preferably rotationally movable). Preferably, according to this embodiment, each of the two opposing lateral mounting projections are mounted on a carriage which is configured to run along a cooperating curved track disposed within the cantie body. Preferably, each of the two opposing lateral mounting projections may be secured in a selected position, defining a desired angle to the cantie body, by a tightening fixing extending through the carriage into a fixing hole in the cantie body. The carriage, which is fixedly extending from each lateral mounting projection may optionally be a curved elongate member coplanar with the cantie body, in which the curve corresponds to the angle of rotation of the lateral mounting projection relative to the cantie body when it moves from a retracted configuration to an extended configuration. Preferably, a track is defined within the cantie body, defined by ribs and fins or a series of posts which define a recess into and through which the carriage may pass. Preferably, there is a guide rail or fin along which the carriage may ride between a retracted configuration and an extended configuration of the lateral mounting projection. Optionally, there are respective stops representing the maximum contraction or extension of the lateral mounting projection relative to the cantie body, which stops may take any suitable form. Preferably, the carriage has an elongate aperture formed therein (which may have the same curvature as the carriage) through which a fixing screw may secure to a corresponding aperture (e.g. on apost) the carriage in a desired location. Preferably there are at least two such elongate aperture and fixing post arrangements in suitable alignment. Preferably, at the selected relative angle of the two opposing lateral mounting projections, the two opposing lateral mounting projections are rigidly disposed relative to the cantie body. The adjustable cantie component may be used as the cantie in any embodiments of the core tree defined above and may serve to stiffen the seat portion (or seat portion component) transversely in order to reduce the torsional flexibility that the core tree (and m particular the seat portion) may have prior to mounting of a cantie. In one embodiment, the modular core tree comprises an adjustable head portion, the headplate angle of which can be adjustably secured by mounting a suitably angled gullet bar thereto, and an adjustable seat portion having sufficient torsional flexibility whereby the cross-sectional shape can be adjusted by the provision of a suitable (and preferably adjustable) cantie component. Preferably, the adjustable cantie component, seat portion component, head portion component and any connecting mid-section are formed of injection-moulded plastic. Preferably, the elongate cooperating longitudinal members are formed of plastic (e.g. injection-moulded plastic) or steel. Tire invention will now be described in more detail, without limitation, with reference to the accompanying Figures. Features common throughout the figures share reference numbers. In Figure 1, there is shown tine underside of a conventional saddle 101 illustrating the recessed spine portion 103 and load-bearing stuffed panels 105 extending along the length of the saddle 101 on either side of the recessed spine portion 103. In use, when the saddle is fitted to a horse, the load-bearing stuffed panels 105 will contact the thoracic region of the horse’s back, either side of the spine and rear of the withers. Whilst the load-bearing stuffed panels 105 provide cushioning between the saddle tree and the horse’s back, they do not allow a great deal of freedom of movement to accommodate the horse’s movement as it walks or runs or the movement of the load as the rider changes position on the horse. Figure 2A illustrates a saddle structure 211 according to the invention, for use in a saddle. The saddle structure consists of a core tree 213 fitted with a gullet bar 207 under a head portion 217 thereof, and a pair of opposing front plate members 219, pair of opposing middle plate members 221 and a pair of opposing rear plate members 223, each one of each opposing pair disposed either side of a central longitudinal axis of the core tree 213 so as to define a spinal recess 203 (illustrated in Figures 2B and 2C, which show a very similar but alternative saddle structure 211 viewed from the bottom and the front respectively) and connected to the core tree 213 by respective rigid elongate front connecting members 225, middle connecting arms 227 and rear connecting arms 229. Each plate member 221, which in use would be provided with a padding material or one or more padding members on an underside thereof for contact with the horse’s back, is of generally rounded-comer square shape and planar and separated from each adjacent plate member by a distance of about 15 mm. The front connecting member 225 may form part of or preferably extend from the gullet bar 207, while the middle and rear connecting arms 227, 229 are each formed of an elongate shaped carbon fibre bracket 231,232 having laterally disposed plate-mounting end portions 233, 234 and a central treemounting portion 235, 236 for affixing the bracket 231, 232 to a corresponding bracket mounting point (not shown) on the underside of the core tree 213 (a closeup view of a rear bracket 232 is shown in Figure 2F). As shown in Figure 2D and 2E, the tree-mounting portions 235,236 of the middle and rear brackets 231,232 may be secured to middle and rear bracket mounting points (not shown) via middle and rear tree mounts 239,240 by screwing or bolting the tree mounting portions 235, 236 to the tree mounts 239, 240, which are adhered into the corresponding bracket mounting points (not shown) on the core tree 213. The front, middle and rear plate mounting portions 241, 233, 234 of the connecting members / arms 225, 227, 229 are provided on one side thereof, for mounting to the plate, with a projecting ball 243, as illustrated in Figure 2G (in relation to the front plate mounting portion 241), which shows the front plate member 219 and the front plate mounting portion 241 in exploded view. The projecting ball 243 may be received in a high wearing plastic bearing 245 (available from Igus GmbH), which together with the projecting ball forms a ball and socket joint. The bearing 245 may be received into ball joint receptacle 247 with a snap fit into an upper side a recess 249 for receiving the bearing 245 and on the other side a circular arrangement of trapezoid fixing projections 251 for receipt into and adhesion to (with an industrial-strength glue) into correspondingly shaped mounting socket 253 formed medially on the surface of front plate member 219. When assembled, as shown in Figure 2A, with leather saddlery (not shown) formed around the core tree 213 and padding material or elements mounted (not shown) on the underside of the plate members 219,221,223, and fitted to a horse, as is shown in Figures 4A and 4B (which is illustrated with an alternative embodiment of the saddle structure), the plate members may first of all, adopt an orientation once in contact with the horse so that the front, middle and rear plate members 219,221,223 do not adopt a common plane and may change orientation in any direction as the horse moves or as the rider moves on the horse so that each contact pad (made up of the plate members 219,221,223 and padding elements) may remain generally in full contact and orientated with the horse’s back at that point. The saddle structure 211 thus adapts dynamically to accommodate and adjust to horse’s body as the horse moves and adapts dynamically to the position and load applied by a rider on the horse. The plate members 219,221,223, as illustrated by the front plate member 219 in Figures 2G and 2H, are thin plates of strong, relatively rigid resilient material (e.g. fibre-reinforced polypropylene or polypropylene-containing polymer blend), having a thickness of approximately 3 mm in the centre thereof feathering to 2 mm at the peripheral edges 255. To assist in the spreading of load across the plate members 219,221,223 and thus the contact pad (so as to reduce the risk of pressure points that may cost pain to the horse), eight load-spreading ribs 257 are formed on the plate members 219,221,223 that extend radially outward from a medial or central portion and taper along their length, which length is such that they may extend about one-third to one-half of the distance to the peripheral edge 255. In order to reduce the risk of pressure points against the horse at the peripheral edges 255 of the plate members 219,221,223 (and thus the contact pads), a degree of relative flexibility in the peripheral region of the plate members 219,221,223 is sought by feathering the thickness of the plate member material and by forming discrete petals 259 at the peripheral region of the plate members 219,221,223 by the formation of slots 261 extending radially inward medially or centrally from the peripheral edges 255, typically by an amount of one-third to two-thirds of the distance from the peripheral edges 255 to the mounting socket 253 of the plate member 219,221,223. Thus, when more load is placed on one side of the contact pads, the petals 259 may flex slightly to reduce the risk of pressure points on the horse and to spread the load across the plate members 219,221,223. In Figure 2H, the radially inward extending slots 261 are shown to intercalate with the radially outward extending load-spreading ribs 257, with the consequence that the load spread by the load-spreading ribs 257 may extend into the respective petals 259. Figure 3 shows in perspective view an alternative saddle structure 311, again comprising a core tree 313 having a head 317 with a gullet bar 307 mounted to an underside thereof and, at the distal end of respective connecting arms (front connecting arm 324 shown), front, middle and rear pate members 319,321,323. Providing the articulating arrangement are, on each plate member 319,321,323, two perpendicularly arranged shaped carbon fibre sprung strips 371 having an overlapping raised central portions (not visible) for mounting to front plate mounting portion 341 and distal plate mounting formations 373 for mounting to the plate 319 via raised connecting platforms 375 formed on the plate 319. The raised central portions and the distal plate mounting formations 373 are separated by angled portions to form the sprung strips 371. They are sprung by being mounted under lateral compression or tension, or may be mounted without compression or tension. The two perpendicular sprung strips 371 define two perpendicular components of resilient adjustability, whereby the plate 319 (and the middle and rear plates 321,323) may be re-orientated in angle in any direction relative to the core tree 313 (and connecting member) depending on changes in tire load applied to the core tree 313 or movement of the horses body and return to the resting position on the return of the load or movement to the starting point. Figure 4A and 4B illustrate a saddle 463 on a horse 477 formed with saddle structure having contact pads, showing a rear contact pad 465 formed of a rear plate member 423 on one side thereof and a padding material 467 on the other side thereof, the contact pad 465 being connected to the core tree (not shown) within the saddle body 469 of tire saddle 463 by way of a connecting arm 429, being part of bracket 432 that is fixed to a corresponding bracket mounting point (not shown) on the core tree (not shown) and to the plate member 423 via a ball and socket arrangement. Figure 4C shows a view from below a saddle 463 resting on a support frame 479 with the saddle 463 supported on the frame by front, middle and rear contact pads 449,450,465. The pair of opposing rear contact pads 465 are mounted onto the core tree 411 via two connecting arms together provided by rear bracket 432 that is fixed to the core tree 411. A recessed spine portion 403 is apparent from the space between opposing contact pads 449,450,465. Figures 5A to 5F show an adjustable cantie component 591 for mounting to a seat portion component 703 illustrated in Figures 7A to 7B for a core tree, especially a modular core tree as illustrated in Figures 8A to G and 9A and B described below. The adjustable cantie component 591, as shown in Figures 5A and 5B in an intermediate configuration, has a cantie body 592 made up of a rear body 595 and a front facing 596, which is fitted into a recess in the rear body 595 and secured in position by a body fixing screw 597. The adjustable cantie component 591 further has a seat-mounting projection 593 extending from the lower portion of the cantie body 592 for mounting to a mounting part 722 at a rear edge 721 of a seat portion component 703. The seat-mounting projection 593 has a medial mounting 598, fixedly, mounted to and extending downward from the cantie body 592, disposed between two opposing lateral mounting projections 594. The opposing lateral mounting projections 594 extend downward and are movably mounted relative to the cantie body 592. Seat-mounting fixing apertures 599 are provided along the length of seat-mounting projection 593. The lower edge 502 of the seat-mounting projection 593 is generally curved, curving downward in the lateral direction. The opposing lateral mounting projections 594 are configured to pivot about pivot points 504 at or between the junction of medial mounting 598 and each opposing lateral mounting projection 594. The opposing lateral mounting projections 594 may pivot about pivot points 504 between a retracted configuration illustrated in Figures 5C and 5D, in which the opposing lateral mounting projections 594 are rotated upwards toward the cantie body 592 resulting m opposing mounting projections 594 being disposed at a larger angle relative to one another (around 180 degrees based upon an imaginary line linking the fixing apertures 599 in each of the opposing lateral mounting projections 594), and an extended configuration illustrated in Figures 5E and 5F in which the opposing lateral mounting projections 594 are rotated downwards, away from the cantie body 592 (through the intermediate configuration illustrated in Figures 5A and 5B) so that they are disposed at a smaller angle relative to one another (e.g. based upon the imaginary line linking the fixing apertures 599 in each of the opposing lateral mounting projections 594). As can be seen in Figures 5D and 5F, in which the front facing 596 has been removed from the rear body 595 to reveal the interior of the cantie body 592, the opposing lateral mounting projections 594 are each provided with a curved carriage member 506 which extend and are moveable along a corresponding track 508 (better illustrated in Figure 5G) within the cantie body 592 to locate the opposing lateral mounting projections 594 in their retracted configuration (shown in Figure 5D) or in their extended configuration (shown in Figure 5F) or at any configuration in between. Figure 5G shows the rear body 595 of the cantie body 592 along with one lateral mounting projection 594, which is in exploded view. The track 508 is formed of projecting ribs and posts to define a curved track perimeter 520 along which the carriage member 506 may move and is guided by guide fin 510 that is punctuated by two guideposts 512 configured to extend through elongate adjustment apertures 514 in the carriage member 506. The carriage member 506 may be secured in place in a chosen configuration (e.g. retracted or extended) by tightening carriage fixing screws 516 in apertures in guideposts 512 through the elongate adjustment apertures 514. In use, the configuration of the lateral mounting projections 594 in the adjustable cantie component 591 may be selected and then affixed to a mounting part 722 of a seat portion component 703 (which may require manipulation of a seat portion component 703) or the adjustable cantie component 591 may be mounted to the seat mounting part 572, via the fixing apertures 599 in the seat-mounting projection 593, before the carriage member 506 is fixed in a particular position along the track 508. Then, the seat portion component 703 may be manipulated, e.g. by pushing down or pulling up lateral rear wings 718 of the seat portion component 703 to flex or tilt them into a desired shape for the seat portion, and then tightening the carriage fixing screws 516 in the elongate adjustment apertures 514 to secure the lateral mounting projections 594 in the desired position and thus hold the shape of the seat portion component 703. In Figures 6A to 6C, a modular core tree 601 is shown with a seat portion component 603, head component 605 and connecting component 607 therebetween, with an adjustable cantie component 691 mounted to the mounting part 622 at the rear edge 621 of the seat portion component 603. The adjustable cantie component 691 is illustrated in its retracted configuration (Figure 6A) in which the opposing lateral mounting projections 694 are rotated into the cantie body 692 to the maximum extent, in an intermediate configuration (Figure 6B) in which the opposing lateral mounting projections 694 are rotated into the cantie body 692 to an intermediate extent and in an extended configuration (Figure 6C) in which the opposing lateral mounting projections 694 are rotated out of the cantie body 692 to the maximum extent. The rear edge 621 adopts a corresponding shape being slightly curved up laterally in Figure 6A, being fairly straight in Figure 6B and slightly curved down laterally m Figure 6C. Thus, the selected adjustment of the lateral mounting projections 694 in the adjustable cantie component 691 can be seen to affect the shape of a rear portion of the seat portion component, which can be adjusted to suit rider preference (and / or horse shape). The flexibility of seat portion component 603,703 is preferably configured to match the arrangement of lateral mounting projections 694 so that adjustment thereof can cause the seat portion component 603,703 to flex accordingly. Lateral rear wings 618,718 are configured to flex or tilt laterally while being longitudinally stiff, so that the shape of the seat portion component 603,703 may adapt according to adjustments made to the adjustable cantie component. This is achieved by the provision of reinforcing inserts 281,781 to stiffen the lateral rear wings 618,718 longitudinally, while transverse reinforcing ribs 724 are provided with transverse discontinuities 726 that improve the lateral flex or tilt of the lateral rear wings 618,718. This flexibility is further enhanced by forward extending slots 628,728 that extend forward from the rear edge 621,721 of the seat portion component 603,703 and are ideally aligned with the pivot points 604 of the lateral mounting projections 694 and with the transverse discontinuities 726. Thus, the lateral rear wings 718 may be flexed or tilted laterally upon adjustment or to fit an adjusted adjustable cantie component, so that a desired seat shape is achieved. In Figure 8A, there is illustrated a core tree in the form of an assembled modular core tree 801 composed of a seat portion component 803 for providing the seating area of a saddle for the user, a head portion component 805 toward the fore of the core tree, and a connecting mid-portion component 807 mounted to and linking both the head portion component 805 and the seat portion component 803. A cantie 809 is mounted to a rear edge 821 of the seat portion component 803 (typically using fixing screws that extend through cantie mounting apertures 847 recessed along the rear edge 821 to fix into a lower flange 849, better illustrated in Figure 8C). The seat portion component 803, connecting midportion component 807 and head portion component 805 form a generally longitudinal arrangement of a core tree, which is typically symmetrical about a vertical plane on its longitudinal axis. The seat portion, connecting mid-portion and head portion components 803,807,805 typically have aligned lateral or outer edges 823, 825, 827 and the cantie lateral edge 829 is typically aligned with the seat lateral edge 823 to give a continuous uninterrupted edge from the fore lateral edge 827 of the head portion component 805, all along the sides of the core tree 801, about tire cantie 809 and back to the opposing fore lateral edge 827. The head portion component 805 is shaped at its fore edge to form a generally arcuate headplate 813 extending along the fore edge of the head portion and extending to peripheral flank portions 831. The peripheral flank portions 831 are disposed at a flared angle relative to the adjoining part of the arcuate headplate 813. The seat portion, connecting mid-portion and head portion components 803,807,805 may be formed of any suitable material that achieves the desired longitudinal rigidity, whilst retaining dimensional stability in use (and being suitable for working and for applying fixings). Typically, they are formed of a filled polypropylene (or other suitable polymer), which may be injection moulded, preferably filled with glass fibres in an amount of about 80 to 30% by weight of the resulting filled polypropylene. The cantie 809 is typically made of plywood, as illustrated, or other similarly rigid synthetic material, so as to introduce further torsional rigidity across the rear half of the modular core tree 801. Tire headplate 813 is configured to receive and be mounted to a rigid, steel gullet bar 811, which is generally of arcuate, elongate bar shape and typically having an arcuate central portion 833, two opposing side bar portions 835, which are typically quite straight, and two flared end members 837, disposed at an angle flared outward relative to the side bar portions 835 and configured to cooperate with the peripheral flank portions 831. The head portion component 805 is preferably configured, as illustrated in Figures 1A to 1G to be sufficiently flexible about the longitudinal axis of the core tree (or more particularly about the apex of the arcuate headplate 813) to accommodate any of a range of gullet bars 811 defining a range of gullet angles (the angle between the opposing side bar portions 835), e.g. from 75° to 110°. The gullet bar 811 may be secured to the underside of the headplate 813 by way of fixing screws 839 through apertures in the gullet bar 811 and corresponding threads (not shown) formed in the underside of the headplate. It is intended that the gullet bar 811 be interchangeable, even after a saddle (not shown) is manufactured on the core tree 801, requiring that the completed saddle will have an accessible pocket accessible from the rear of the pommel at the underside of the head portion component 805 allowing access to the underside of the headplate 813 and the gullet bar 811 and enabling the fixing screws 839 to be removed, the gullet bar 811 removed and replaced with another with a different gullet bar angle and re-secured to the headplate 813, the angle of which will adjust accordingly, whereby the saddle can be adjusted or fitted to different horses. The gullet bar 811 is shown more clearly, exploded from the headplate 813, in Figure 8B. Stirrup bars 815 may be provided on the head portion component 805, preferably mounted in two locations, such as adjacent the peripheral edge 827 and onto the flank portions 831, for a robust mounting. Front connecting members 225 (not shown here) may be mounted on to the flank portions 831, optionally in cooperation with the stirrup bars 815. The seat portion component 803 and the head portion component 805 are mounted together via the connecting mid-portion component 807 as better illustrated in Figure 8D and 8E (showing the seat portion, connecting mid-portion and head portion components 803,807,805 with the seat portion component 803 removed) and in Figure 8F and 8G (showing the head portion and connecting mid portion components 805,807, with the connecting mid-portion component removed). Seat portion component 805 is configured to mount to the connecting mid-portion component 807 by way of an upper seat flange (or upper seat overlapping projecting member) 851 to the fore of the seat portion, which extends the full width of the seat portion component 805 and has forward projecting peripheral elongate members 853, the flange 851 being mountable to a cooperating recess in the connecting mid-portion component 807 forming lower rear mid-flange (or mid-portion lower overlapping rear-projecting member) 855. To provide a robust mounting, to allow the transfer of load between and to reduce the risk of a weak point at a joint between the seat portion component 803 and the mid portion component 807, a significant degree of overlap between the upper seat flange 851 and the lower rear mid-flange 855 is provided, typically from a quarter to a half of the longitudinal extent of the seat portion component 803. A seat front edge 857 abuts a mid-rear edge 859 of a core element 861 (being the part of the upper surface of the connecting mid-portion component 807 that overlies the longitudinal axis of the core tree 1). The connecting mid-portion component 807 and the head portion component 805 are also mounted together by overlapping projecting portions and corresponding recesses. The connecting mid-portion component 807 is provided with a forward projecting mounting element or flange 863 comprising forward projecting mid-portion peripheral elongate members 865 configured to cooperate with corresponding peripheral head recesses 867 extending along a major part of the longitudinal extent of the head portion component 805. Lower rear-projecting elongate head members 869 are received in cooperating recesses (not shown) in the underside of the core element 861 of the connecting mid-portion 807. These cooperating elongate members and overlapping flanges, which also define midportion front edge871 and head portion rear edges 873 that abut, serve to provide longitudinal stiffening of the core tree 801 and to provide robust mounting reducing the risk of a weak point at the joint. Multiple mounting fixings 875 are provided to secure the flange members 851,863 of the seat component 803 and mid-portion connecting component 807 and associated projecting elongate members 853,865 to the midportion connecting component 807 and head component 805 respectively (and to receiving recesses thereon), typically extending through apertures in the flange members 851,863 and received by receiving threads in the corresponding portion of the mid-portion connecting component 807 and head component 805. For example, a mounting fixing 875 is provided to a fore and rear overlapping portion of a projecting elongate member 853,865 and the corresponding part of a recessed mid-portion connecting component and head component thereby providing a robust, reinforced elongate peripheral portion, 877,879 of each of the mid-portion connecting component 807 and the head portion 805. These reinforced peripheral portions 877,879 are thereby provided with increased stiffening or rigidity in a longitudinal direction relative to the remainder of the mid portion connecting portion 807 and head portion 805 and thereby enable potential transfer of load. Typically, the point of contact with the greatest load between saddle and horse is facilitated at or around the flank portions 831 of the head component 805 of the core tree 801, since there is typically a point of contact at the flank portion 831 and, potentially, peripheral portions of the headplate. The provision of the stirrup bars 815 proximal to or mounted on the flank portions 831 leads to a potential concentration of load on the horse at or proximal to the flank portions 831. By providing reinforced elongate mid-head and reinforced elongate seat-mid peripheral portions 877,879, for example through the overlapped mounting of forward projecting seat elongate members 853 to the mid portion connecting component 807 and through the overlapped mounting of the mid portion peripheral elongate members and the head component 805, that are aligned (e.g. longitudinally aligned or generally aligned front to back insofar as the elongate path of respective reinforced peripheral portions 877,879 continues from one to the other) and are proximal, preferably adjacent or adjoining, load can be transferred from the flank portions 831 or proximal thereto along the length of the reinforced elongate mid-head and reinforced elongate seat-mid peripheral portions 877,879 and therefor along the outside edge of the core tree. Thereby load may be spread along the outside edge of the core tree and along the flanks of the horse. The elongate stiffening and reinforcement of the peripheral portions of the core tree is further provided along the periphery of the seat component 903 and toward the rear thereof by providing reinforcing inserts 981 into a corresponding peripheral recess 983 of the seat component 903 as illustrated in Figure 9. These are secured in place by insert fixing 982 (receiving through apertures of the inserts 981 and into corresponding receiving apertures or threads provided in the recess 983). The resulting reinforced elongate peripheral seat portion 984 extends generally longitudinally and is adjacent to or abuts the reinforced elongate seat-mid peripheral portion 977 thereby extending the longitudinally stiffened load transferring peripheral portions of the core tree 901 from the flank portions 931, via reinforced elongate mid-head and seat-mid peripheral portions 977,979 to the full length of the core tree 901, thereby allowing effective spread of the load upon the flank portions 931 or proximal thereto along the full length of the core tree. Middle and rear bracket mounting portions 985,986 are provided for mounting to brackets (see, e.g. Figure 2G) via middle and rear tree mounts (see 239,240 in Figures 2E and 2F). Torsional stiffness to a desired degree is provided by a combination of the general structural integrity of the core tree 801 in combination with torsional stiffness reinforcement features of, in particular, the seat component 803, the connecting component 807 and the cantie 809,which together define a reinforcing ‘box’ in which there the connecting component 807 is reinforced with an overlapping flange and reinforcing vanes in longitudinal and lateral orientation across its full width, which is adjacent to the reinforcing peripheral portions of the seat component 803 that extend back to the rear-edge of the seat portion in contact with the cantie, which is of rigid form (e.g. plywood). Together, these stiffening forms in a box shape on the body of the core tree, provide the desired degree of torsional stiffness. Also contributing to the torsional stiffness is the combination of reinforced mid-head elongate peripheral portions 879 which are linked, at the head end, by the arcuate headplate 813 and gullet bar 811 which is a rigid steel member. Tire longitudinal stiffhess / rigidity is preferably of a range of 60 to 80 N / mm which may be measured by an arrangement as illustrated in Figure 10A. In Figure 10A, a rig 1001 is provided comprising fore support posts 1003 for supporting the flank portions and gullet bar of a core tree and rear support posts 1005 for supporting the rear part of the seat of the core tree. Fore, mid and rear strain gauges 1007,1009,1011 are disposed on the rig 1001 configured to engage with a mid-point of the core tree (in the case of gauge 1009), which is typically the narrowest point and the mid-points of the head and seat portions of the core tree in the case of gauges 1007,1011. To measure the longitudinal rigidity, a length of webbing was disposed over the approximate centre of tine core tree and loaded with a weight (in the form of a dumbbell bar with weights loaded onto the ends thereof). Additional weights were successively loaded and strain gauge measurements taken. A value for longitudinal rigidity is calculated from the measurements from the strain gauges. Torsional stiffhess / rigidity of a core tree is preferably of a range from 110 to 130 N / mm which may be measured by an arrangement as illustrated in Figure 10B. In Figure 10B, a torsional strain rig 1013 is provided comprising a gullet support member 1015, which in use, is clamped to the gullet bar / headplate of the core tree to secure it in place relative to the torsional strain rig 1013, and a pivotally mounted cross-member 1017 provided with rear-seat rotatably-mounted support pads 1019 for supporting two opposing peripheral portions of the seat of the core tree, preferably mid-points of the seat portion (e.g. the widest part of the core tree). The core tree (not shown) may be clamped to the pivotally mounted cross-member 1017 to keep it in place. Two strain gauges 1021 are provided on the rig to engage with the undersides of the pivotally mounted cross-member 1017, one at each side of the core tree. A mass (not shown) was suspended from one side of the pivotally mounted cross-member 1017 and vertical displacement as measured by the strain gauges 1021 recorded and then repeated with incrementally increasing suspended mass. The torsional stiffness may then be calculated from the readings obtained. EXAMPLE A saddle as described above in relation to Figure 4A fitted with a saddle structure similar to that shown in Figure 2A, with foam material provided as the padding material to tire underside of each plate member, was fitted to a horse over a pressure mat used to measure the pressure against the horse’s body at the interface between horse and saddle. The horse was then ridden by a rider following a series of simple exercises including figure of 8s and small jumps around a pre-defined path. The same horse was fitted on the same day with a conventional saddle, such as that shown in Figure 1, and ridden by the same rider following the same series of simple exercises following the same pre-defined path. The resulting pressure maps are shown in Figures 11A (the horse with tire saddle of the invention fitted) and 1 IB (the horse with the conventional saddle fitted). As can be seen from Figures 11A and 1 IB, the saddle of the invention gives a much more even spread of pressure, with no notably discernable pressure points, compared with the conventional saddle which has notable pressure points in the front half of its load-bearing stuffed panels. The saddle of the present invention appears to provide more even load distribution to the horse both across the contact pads (relative to respective portions of the load-bearing stuffed panels of the conventional saddle) and along the total cumulative length of the contact pads compared to the conventional saddle. It also appears to have a much lower maximum pressure. As shown in Figures 11A and 1 IB, the maximum pressure that results from tire saddle of the invention under the test is 11 kPa, whereas with the conventional saddle, the maximum pressure is greater than 28 kPa and, in relation to the front half of the load-bearing stuffed panel of the conventional saddle, there are large areas where the pressure is 15 kPa or more. Thus, the configuration of the saddle according to the present invention serves to distribute the load more evenly across the horse’s back and 5 significantly reduces the amount of pressure felt by the horse. The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the 10 scope of the invention.

Claims

1. A saddle structure comprisinga core tree configured for disposal along a length of, and centered around, a horse’s spine;a plurality of contact pads disposed laterally of a central axis of the core tree and disposed along the length of the core tree, for contacting with a horse’s backone or more connecting members configured to connect the core tree to the contact pads, the saddle structure being configured such that the position and / or angle of the contact pads or each contact pad may change, relative to the position and / or angle of the core tree, preferably responsive to the position and extent of load applied to saddle in use.

2. A saddle structure as claimed in claim 1, wherein the core tree has a rigid axial portion and preferably is substantially rigid.

3. A saddle structure as claimed in claim 1 or claim 2, wherein the one or more connecting members are substantially rigid members and are fixedly and / or rigidly mounted to the core tree.

4. A saddle structure as claimed in any one of the preceding claims, wherein there are at least two contact pads disposed laterally to each side of the central axis of the core tree, preferably at least three pads, arranged from fore to rear.

5. A saddle structure as claimed in claim 4, wherein the contact pads define a cumulative contact area of up to 2500 cm2, preferably up to 2000 cm2, preferably at least 500 cm2, more preferably at least 1000 cm2, and still more preferably at least 1500 cm2.

6. A saddle structure as claimed in claim 4 or claim 5, wherein each contact pad or the contact area of each contact pad is independently separated from eachadjacent contact pad by a distance in the range of from 1 to 10 cm, preferably up to 5 cm, more preferably up to 3.5 cm, still more preferably up to 2.5 cm and most preferably from 1.5 to 2 cm.

7. A saddle structure as claimed in any one of claims 4 to 6, wherein the contact pads each define a substantially rectangular or square contact area.

8. A saddle structure, as claimed in any one of claims 4 to 7, wherein a centre point of contact area of each contact pad is independently disposed laterally from the longitudinal axis of the tree core by a distance in the range from 7 to 15 cm.

9. A saddle structure as claimed in any one of the preceding claims, wherein each of the contact pads is configured to articulate relative to the core tree and / or the connecting member to enable the position and / or angle of each contact pad to change, relative to the position and / or angle of the core tree, responsive to the position and extent of load applied to saddle in use and / or the movement of a hose to which the saddle structure is fitted.

10. A saddle structure as claimed in claim 9, wherein the or each contact pad has an articulating arrangement to which a connecting member is mounted or through which a connecting member is mounted to the or each contact pad.

11. A saddle structure as claimed in claim 9 or claim 10, wherein the contact pad comprises a plate member having disposed on, against or in relation to one face thereof one or more padding elements or padding material, for contacting with a horse's back, and being configured for connecting to the connecting member on the other face thereof.

12. A saddle structure as claimed in claim 11, which further comprises an articulating arrangement linking the plate member to the connecting member or forming part of the plate member and onto which the connecting member may be mounted.

13. A saddle structure as claimed in claim 12, wherein the articulating arrangement is selected, independently for each contact pad or opposing pair of contact pads, from one or a combination of: one or an array of resiliently compressible mountings; an arrangement of resiliently deformable load-spreading brackets; and a ball and socket joint.

14. A saddle structure as claimed in claim 13, wherein the articulating arrangement is a ball and socket joint, wherein a socket portion is formed or mounted on the plate member and a ball portion is formed or mounted on the connecting member, wherein the ball portion and the socket portion are configured to cooperate so as to allow the plate member to change in angle relative to the connecting member and the core tree.

15. A saddle structure as claimed in any one of claims 12 to 14, wherein the articulating arrangement is disposed in relation to a medial portion of the plate member.

16. A saddle structure as claimed in claim 15, wherein the plate member comprises a peripheral portion surrounding the medial portion, wherein the peripheral portion is divided into a plurality of petals extending peripherally outward from the medial portion and separated from adjacent petals.

17. A saddle structure as claimed in claim 16, wherein the plate member has a thickness which feathers out from medial portion to a peripheral edge of the peripheral portion.

18. A saddle structure as claimed in any one of claims 15 to 17, wherein the plate member comprises a plurality of load spreading ribs, at least a portion of which radially extend from the medial portion of the plate member.

19. A saddle structure as claimed in any one of the preceding claims, wherein there is provided a plurality of connecting members such that a discrete connecting member connects each contact pad or each pair of opposing contact pads to the core tree.

20. A saddle structure as claimed in claim 19, wherein each connecting member comprises a rigid ann extending from the core tree, wherein each rigid arm is formed of carbon fibre or steel.

21. A saddle structure as claimed in claim 20, wherein each pair of opposing rigid arms is formed from a single length rigid material mounted to an underside of the core tree.

22. A saddle structure as claimed in claim 20 or claim 21, wherein the rigid arms are mounted to the core tree via a mounting platform formed on an underside of the core tree.

23. A saddle structure as claimed in any one of the preceding claims, wherein the core tree is a modular saddle tree comprising an assembly of a plurality of prefabricated component parts, the assembly comprising at least:a seat portion component; anda head portion component, wherein the seat and head portion components are secured relative to one another by elongate longitudinal members, whereby a desired longitudinal rigidity is provided to the core saddle.

24. A kit of parts comprising a core tree, preferably as defined in claim 23, a plurality of contact pads and one or more contacting member configured for mounting to the core tree and connecting to the contact pads, which parts may be assembled to form the saddle structure as defined in any one of claims 1 to 23.

Images