If you are an eBay user and you use it to sell items, you can help the DSA easily as you sell your unwanted items.
When uploading your items for sale search for the Dwarf Sports Association UK within the charitable giving section of the online form.
Then decide on the percentage of the final sale price you would like to donate to the DSAuk, when your item has been purchased that percentage will be automatically donated to the charity.
It's really easy to do. Try it next time you sell an item with eBay.