Hi

I think I read somewhere that Jessops do background paper rolls, don't know what sizes they come in probably 6 feet by 4 feet. I have a sheet of green material that I got in a drapers shop of all places. It's not the genuine article but if it's lit correctly and you are using reasonably good video editing/compositing software you should still be able to pull off a good matte from it. Having consistent lighting is the key, if you can get your hands on a small light meter and take readings (if your really serious about it) then this is the 'torture' I would go through. Make sure you get rid of any creases and wrinkles as they make life just a tad for difficult.