ledhut.co.uk have some good ones - I've been trying a few and have been very impressed.
Quidco cashback available, and often a 25% code around (there is today for example). Next day delivery with DPD (so it actually arrives) is only 2.99 as well which seems perfectly fair.
If you get the discounts and order at the right time, they are becoming quite cost effective now. I've been impressed at the quality (both of the lamp, and the light :-) ) so far... Can't comment on the life though yet :)
They do offer a 5 yr warranty although you have to post them back a form for that IIRC.
No connection beyond being a happy customer
Darren