People on here have said its around 2-5 working days for EVGA & some of the other brands based in Europe.EVGA aren't UK based, its Germany, so you are still looking at 1-2 weeks complete turnaround
Not sure PNY, KFA2 or Zotac have actual UK RMA either - there were some comments from a while back that PNY handle RMA out of france
Asus also do have UK RMA
the main problem doesn't seem to be where the AIB have RMA, but OCUK keep advertising "quick turnaround" on certain brands and then when people actually do an RMA they get told 28 days
http://forums.overclockers.co.uk/showpost.php?p=28578976&postcount=2
This is based on a thread Nelly used to maintain which had peoples RMA experiences but was closed last month & is no longer updated.