Are you quite sure you want an AMD card for £200? There's currently
a really hot offer on the GTX 670, which is going for about £200. I can't think of an AMD card that can beat it for price-performance.
However, if you really really want AMD, then I'd probably recommend the
Gigabyte HD 7950, which has 2 PCIex6 power connectors, and is almost as capable as the GTX 670.