I put together this build, brands and such could be changed, but it is right at your budget and would perform quite well on most games; http://pcpartpicker.com/p/bnrYf7
There is still room to shave off some cost as well.
Unfortunately a straight dollar to sterling conversion of US prices doesn't quite work. We pay more for stuff over here!
Here's what you get if you use the UK prices (I changed the Sapphire card which was not for sale here to the cheapest R9-270 available as a substitute) but it's well over £400 - http://uk.pcpartpicker.com/p/cYFKnQ
Mail ordering from the US isn't really an answer either because imports are charged 20% VAT on the overall value, and shipping costs are sky high.
Edited by jonuk76, 13 September 2014 - 07:19 AM.