I thought it might be useful to repost sethstarkadder's earlier post with instructions for the letter makers.
You can use any colour, any fabric, check, flowery, plain, any material, cotton, wool, silk, nylon, etc. Please check for colourfastness beforehand in case we get rained on. If you would like to embellish further using embroidery, crazy patchwork, potato printing, Mooncup art, etc, that is also fine. If you would like to knit, felt, crochet, make Honiton lace, embroider on it, weave lentils, etc, that is fine too.
The letters will be applied using Bondaweb. I can get some and send you a bit if you PM me your address. The method is, you make a template of your letter then iron your fabric onto bondaweb, then draw round the template and cut out the bondaweb and fabric together. You don't need to hem it. You will then send me your letter backed with bondaweb which I will iron onto the banner, then zigzag round on the sewing machine.
If you are doing something like crochet which might not work very well with bondaweb, don't worry, I'll just sew it on any way that works.
(Then if I get zigzag fatigue halfway through I'll post it to someone else to take over)