Man of Honour
Now that OCUK finally sells them, the EVGA GQ 650w is a very good psu. It's cheaper than the Superflower and is a extra 100w. The downside is that it's semi-modular but only the 20+4 pin is hard wired so you will be using that anyway. It's built by FSP and also has a 5 year warranty. There is a review here.
It's also worth noting that EVGA has a UK rma centre.
It's also worth noting that EVGA has a UK rma centre.