I'd also really recommend an American guy called Vic who is based in a company called Midland Mars in Bloxwich, near Walsall. He's good value and uses only top quality film - sure he could also source something particular if you required.
I've only had my car about two months but am a bit particular and the poort quality tint on the rear screen of my E30 was bugging me everytime I looked in the rearview mirror. He removed the old tint film from my rear screen and re-tinted it last Saturday and it's perfect. Midland Mars has a website which is pretty basic but could be worth look and a chat on the phone to Vic. I also have his mobile if you're interested.