Nothing wrong with the AutoGlym kit, gaz. Esp. the SRP that Liam mentioned. (BTW, Liam, you should ALWAYS clay the car AFTER it's been washed.. You simply cannot clay over a dirty car!? Scratch-galour!)
I was supposed to be down your way today infact.. Ashby Forville to visist a rather nice Porsche Carrera 4S. However, the boiler blew-up last night, so, I've had to stay in and wait for Mr. Boiler-Man to come and fix it!
If you're ever up near me (Newark-On-Trent..) be sure to give me a shout.
For black, I'd probs reccomend Victoria Concours for looks.. but, Collinite 476s for durability.