I've tried using black sheets of paper for backing a board, but it isn't hard wearing enough, particlarly splash proof so I want to try some coated material like buckram, but I can't find anywhere that sells it in small (1m^2) amounts. Everywhere I've asked wants to sell me 100m of the stuff!
Anyone in the UK know where I might look?
There are sources online that sell a variety of cover material suitable for turned edge applications (like board binding or backing).
Cover Material Sales Inc. \ has a large variety available. A quick call confirms that their minimum order for any item is a 5 yard length (which will make anywhere from 10-16 or more boards depending on board size).
I have seen book cloth in art stores in sizes large enough for a game board, but they are prohibitively expensive ($15-18 per square meter, approx). For the price, you'd be better off going with one of the larger suppliers and getting more than you need and stocking up for future products.
Best of luck!