http://www.overclockers.co.uk/showproduct.php?prodid=BU-006-GI&groupid=701&catid=6&subcat=2858
http://www.overclockers.co.uk/showproduct.php?prodid=CA-143-NX&groupid=701&catid=123
http://www.overclockers.co.uk/showproduct.php?prodid=MY-000-AR
http://www.overclockers.co.uk/showproduct.php?prodid=GX-019-VX
£502
You could drop the CPU down to the anniversary Pentium & up the GPU & slightly better board and then overclock the CPU like mad as it's made for it!
PSU is OK (Nothing wrong with Evga), would grab the Superflower 550W Gold if the budget would allow (better efficiency & SF are top of their game).
The motherboard does leave a lot to be desired.