Really really really bad choice, for tenner more he could have 5750 which is like 4 times faster.
Budget of £80. If his budget was around £90 then I would advise this
£91 XFX ATI Radeon HD 5750 XXX 1024MB
http://www.overclockers.co.uk/showproduct.php?prodid=GX-186-XF&groupid=701&catid=56&subcat=708
If the OP does not care about memory capacity then this
£76 XFX ATI Radeon HD 5750 512MB
http://www.overclockers.co.uk/showproduct.php?prodid=GX-155-XF&groupid=701&catid=56&subcat=708