TITLE A Sprung Display Case for Dispensing Products DESCRIPTION Field of Invention The present invention relates to the display of products in retail stores. The present invention provides an improved case for the display of products at an easy to reach height, in an enticing position. This can increase impulse purchases and make products more visible to consumers. Background Sprung display cases for various products have been available for a number of years. Perhaps the most common sprung display case are newspaper bins wherein a stack of newspapers are displayed in a vertical bin on a horizontal sprung platform. The bin is sized and shaped to conform to the size of the newspapers stacked therein. The sprung platform is formed such that the uppermost newspaper of the stack is always held at or about the top of the display case. That is, when a newspaper is removed from the bin the reduction in weight on the platform allows the platform to move a distance towards the top of the bin that is substantially equal to the thickness of the newspaper that has been removed. This is achieved by mounting one or more resilient compressible members, for example a spring, within the bin between a lower surface of the platform and an upper surface of the base of the bin. The resilient compressible member will be of a suitable strength to achieve the required displacement of the platform when a newspaper is removed. In this manner newspapers can be displayed in a simple manner that avoids the need for consumers to bend down and pick a newspaper from the bottom of a bin. In light of the success of newspaper bins there has been a drive to provide display cases for a more varied range of products. Sprung display cases for various products have been produced with varying degrees of success. Generally sprung display cases have been considered suitable for products that are sold in relatively high volume in standard shaped packages, such as cuboid packages. It has been found that sprung display cases can improve sales of a product, increasing impulse purchases and making products more accessible to consumers. GB2569192A discloses an improved sprung display case for dispensing products. The display case of GB2569192 is particularly suitable for dispensing heavy products, such as beverage multipacks. There have now been further attempts to create sprung display cases for a variety of other products that are typically stocked on shelves. This has been done to increase sales of the products. Summary of Invention The present invention also provides a sprung display case for dispensing products, the case comprising: a chamber having an upper end and a lower end, open at an upper end and sized and shaped such that a plurality of the products can be stacked within the chamber; a platform mounted to be slidable within the chamber; an upwards biasing means mounted in the chamber between a lower side of the platform and the lower end of the chamber to bias the platform towards the upper end of the chamber; wherein one or more vertically oriented dividers are located within the chamber adjacent the upper end of the chamber. Dividers provided in the chamber adjacent the upper end of the chamber can be used to maintain products in an appropriate position as they reach the upper end of the chamber. This is particularly useful when products are stacked on the platform in layers and each layer contains multiple products. The multiple products in each layer may be any suitable product including but not limited to cans, bottles, or small boxed products. The dividers will be positioned and/or products will be stacked on each layer such that as the platform moves upwards towards the upper end of the chamber the dividers slide between adjacent products on each layer. This may occur as the layer becomes the uppermost layer of products i.e. all products on layers above the relevant layer have been removed from the display stand. This is advantageous as when products are started to be removed from the relevant layer the dividers maintain the products in their position on the platform. This can be particularly advantageous if the platform is not horizontal and is angled away from the vertical as, without dividers, products may fall out of position when adjacent products on the same layer are removed from the layer; suitably formed dividers can prevent this from happening. The platform may not be horizontal in embodiments of the present invention in which the chamber is angled away from the vertical. Dividers of the present invention may be formed in any manner apparent to the person skilled in the art. In embodiments of the invention the, or each, divider of a sprung display case according to the present invention may consist of a substantially vertically oriented planar plate, for example formed of sheet metal or plastic. Embodiments of the invention may have any suitable number of dividers depending on the products intended to be displayed on the platform. Dividers may be formed and positioned to be between adjacent products on the platform. In embodiments of the invention the display case may have only a single divider, in alternative embodiments the display case may comprise a plurality of dividers. Dividers may be positioned in any appropriate manner. In embodiments of the invention one or more dividers may extend forwards from a rear side chamber. One or more dividers may extend rearwards from a front wall of the chamber. One or more dividers may extend laterally across from a lateral side wall of the chamber towards an opposing lateral side wall of the chamber. A sprung display case may have only laterally extending dividers or may have only dividers extending from a front or rear wall of the chamber. Alternatively, a sprung display case may have one or more laterally extending dividers and one or more dividers extending from a front or rear wall of the chamber. A divider may extend completely from one side of the chamber to an opposing side of the chamber. Alternatively, a divider may extend only partially across the chamber, for example a divider may extend less than two-thirds of the distance across the chamber from a first side to a second side or less than half of the distance across the chamber from a first side to a second side. In embodiments of the invention the platform and the or each divider may be formed such that he platform cannot move upwards beyond the lowermost part of a divider. That is, one or more dividers may be formed as a stop to prevent further upwards motion of the platform or may be positioned immediately above the uppermost position of the platform if an alternative or additional stop is provided. A platform of a sprung display case according to the present invention may be formed with one or more slots formed therethrough such that the platform can move upwards past a lowermost part of one or more dividers. The platform of the sprung display case may be formed with one or more slots formed therethrough such that the platform can move upwards past a lowermost part of one or more dividers. That is, one or more dividers can extend downwards along the chamber, past the platform as the platform moves upwards through the chamber. This can allow the products on the platform to be maintained in position downwards through the chamber, in each layer stacked on the platform. In embodiments of the invention one or more dividers may extend the full length of the chamber. In embodiments of the invention one or more dividers may extend part of the length of the chamber. Depending on the positioning of any such dividers slots may be formed in the platform in an appropriate manner. A sprung display case according to the present invention comprising one or more dividers may be formed such that the chamber is vertical. Alternatively, a sprung display case according to the present invention may be formed such that the chamber is angled away from the vertical by between 2° and 45°. The sprung display case is a case that can be used for displaying any suitable good, including but not limited to small or large boxed goods, canned goods, bottles, and mutlipacks. Substantially any good that can be displayed on a sprung display case according to the prior art can be displayed on a sprung display case according to the present invention. A sprung display case according to the present invention may have any feature of a sprung display case according to the prior art. The biasing member may be any member suitable for biasing the platform towards the upper end of the chamber. In embodiments of the invention the biasing member may comprise one or more springs. Angling the chamber away from vertical is advantageous in that acts to ensure that products will not fall out of the sprung display case as the platform is raised. In particular, products positioned on the platform will be maintained at a rear wall of the chamber by angling of the chamber and the correspondingly angling the platform on which the products are located. Products placed on the platform will fall towards the rear wall of the chamber. In order to ensure that products are maintained within the sprung display case a rear wall of the display case may extend upwards beyond an uppermost position of the platform to ensure that products falling towards the rear wall of the chamber will be maintained on the platform by said upwardly extending portion of the rear wall. As will be readily understood the rear wall is the wall towards which the display chamber is angled away from the vertical. The chamber of the present invention may be angled away from the vertical by any suitable angle that allows it to operate. In embodiments of the invention the chamber may be angled away from the vertical between 2° and 25°, between 2° and 10°, or between 5° and 10°. Generally, the platform will be angled away from the horizontal by the same angle at which the chamber is angled away from the vertical in order to maintain the platform at 90˚ to the walls of the chamber. This ensures the platform can move freely within the chamber. However, in embodiments of the invention the platform may be at different angle to the walls of the chamber. A chamber of a sprung display case according to the present invention may be sized or shaped in any appropriate manner. In embodiments of the invention the chamber may have a square, rectangular, triangular, circular, or oval cross-section. Alternatively, the chamber may have any suitable shaped cross-section to conform to the products intended to be placed on the platform including an irregular cross-section if desirable. Further features and advantages of the present invention will be apparent from the preferred embodiments that are shown in the drawings and is described below. Unless otherwise, indicated by context any feature shown in the embodiments of the Figures can be included in an embodiment of the invention independent of any other feature. Drawings Figure 1 is a perspective view of a first embodiment of a sprung display case according to the present invention; Figure 2 is a side view of the first embodiment of a sprung display case according to Figure 1; Figure 3 is a front view of the first embodiment of a sprung display case according to Figures 1 and 2; and Figures 4 and 5 show an alternative embodiment of the invention. A first embodiment of a sprung display case 1 according to the present invention is shown in Figures 1 to 3. The sprung display case 1 has a base 2, with a triangular chamber 3 extending upwardly from the base 2. A platform 4 is mounted within the chamber 3. A spring 5 is formed between the base and the platform 4 and acts to bias the platform upwards towards an upper end 6 of the chamber 3. A rear wall 7 of the chamber 3 extends upwards above an uppermost position of the platform 4. Two dividers 8 are mounted to the rear wall 7 of the chamber 3. The dividers 8 each extend forwards from the rear wall 7 of the chamber 3 approximately one third of the distance to a front side of the chamber 3. The dividers 8 are evenly spaced along the rear wall 7 of the chamber 3 such that they act to divide the rear wall into three portions of equal width. The dividers 8 are positioned to act as a stop to prevent upward motion of the platform 4 below their lower edges. A portion of the rear wall 7 extends upwards above the dividers 8 to allow appropriate signage (not shown) to be mounted on the display case 1. As best shown in Figure 2, the chamber 3 is angled away from the vertical by approximately 5°. This ensures that products (not shown) mounted on the platform 4 fall towards a rear of the chamber 3 as they reach the top of the chamber 3. In particular, this embodiment is designed such that six products are stacked on each layer of products on the platform 4: three in a line at a rear of the chamber, two in a line in front of the rear three, and a final product in at a front of the platform 4. As products are removed from an uppermost layer the remaining products of that layer will slide towards the rear of the platform 4 if product closer to the rear is removed. The dividers 8 ensure that the rearmost products of the uppermost layer remain appropriately spaced on the platform 4. As will be readily understood, the chamber 3 shown in the first embodiment is triangular but it could be of any suitable shape. A second embodiment of a sprung display case 1 according to the present invention is shown in Figures 4 and 5. The sprung display case 1 has all of the structural features of the first embodiment and operates in substantially the same manner. The same reference numerals as used for the first embodiment have been used to indicate the features of the second embodiment. The second embodiment differs from the first embodiment in two ways. First, the chamber 3 has a square cross section. This allows different products to be stacked in the chamber 3 and/or different numbers of products to be stacked on the platform 4. As the chamber 3 has a square cross section the platform 4 is also square. Second, the dividers 8 are formed to extend completely across the chamber 3 from a rear side to a front side. The dividers 8 act to hold products in position on the platform 4. As will be readily understood, the dividers 8 are located such that they slide between adjacent products on the platform 4 as the platform rises up the chamber 3. Thus the second embodiment is intended to have at least three adjacent rows of products on each layer of products stacked on the platform 4.