Okay, I'm not from the UK, but I'm guessing people will give you replies stating shops like Planet, Smartparts, London paintball supplies, and the other ones that have come by over the course of time.
Also, it may be worthwhile getting in touch with Steve Bull, as he travels around a lot, and may just be visiting a tourney near you soon.......He'll probably be able to hook you up with a thing or two.....