As another alternative, I've got an ATI X800 PRO PCI-EX and it was about $150 (Not sure how that translates too pounds) And it's performed amazingly for me. It's got 256mb memory, and SM 2.0.
As far as games application, I can run F.E.A.R. at 1280x960 2xAA 16xAF all setting full except soft shadows, and it's a very playable speed. So, in my opinion, it's a good card

(And if you don't know what F.E.A.R. is, google it.)