I had heard tell of a magical place full of fabric treasure troves called Walthamstow Market. I used a map I found on the internet to make sure I did't miss any. In actual fact I don't think you need a map. Just keep a keen eye out and make sure look behind the many stall for the fabric shops. I started off trying to take a photo of each stall and shop to help you find them but it was so hard because the stall and shops are so closely crammed in - but here's a couple.
Here's my haul (approx 35m of it!)