I’ve bought from him too. His fabric is thinner than the fabric I was replacing, but equally strong and light-tight. (I think it might be rubberized silk?)
Now I think about it, I’ve also bought it from Micro-Tools in California, during covid when Nobby Sparrow wasn’t shipping. It seemed to be the same material. (Don’t let google redirect you to Micro-Mark; scroll down to Micro-Tools.com)