i got mine on ebay from HK. paid over �30 each for them but i see there are plenty of people doing doing similar units now. a quick seach on ebay and i found these:
these are uk based - or so it says in advert.
http://www.ebay.co.uk/itm/XM-L-XML-T...3D271982147340
these are the same but cheaper and you get two but are from china
http://www.ebay.co.uk/itm/2x-Univers...MAAOSwKfVXDfxU
or maybe these, single cree unit but is listed as 30w
http://www.ebay.co.uk/itm/2x-30W-U3-...EAAOSwYlJW5op~
one of mine stopped working too but for the price i think they are still a top buy. my original ones are three led and i replaced it with a four led. the older second one is now filling with water so due for replacement too. they get used in all weathers and there is over 72K miles on my bike so they are a good buy. the ebay shop in the second two links were doing the exact one at �10 each but they have stopped listing it and are now showing those above.