Thanks Lyn, I had seen one option from Wingham, the replacement blending board cloth, £28 for 12x8", but not the others. I am wondering if the drum carder replacement cloth is the same, it looks like it is, and I could buy it by the inch, and go a bit smaller maybe.
By the way I read Wingham used to use plated pins but the stainless proved better quality so they switched, so that answers that.
I know people who have made ther own with fine carding cloth and they work well. I believe the on ones meant for blending boards are longer than reg drum carder cloth but I bet it just depends on the brand of carding cloth.