Lizzy/Sarcy
I'm pretty sure that they pulled out of the UK quite recently. I did a search of the UK web at the time and the only place I could find offering them over here was in Scotland, and when I rang them they said they weren't available any more (they'd just not removed them from their web entry).
I got mine from rei.com. If you follow this link:
http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=1175577&parent_category_rn=4500606
... it should take you there.
I've got a name-dropping anecdote about them, actually. I mentioned to my sports masseur that I was looking for them, and he got into his mind that it was the Clif Bars I was interested in rather than the Shots (the bars are pretty good, too). As well as servicing middle-of-the-pack runners like me he has some serious runners as clients, one of whom is Sonia O'Sullivan. Anyway she was going over to New York for some pre-marathon publicity so he asked her if she could get me some of these bars. When I turned up next time there they were waiting for me. But better still, Sonia was the next session after me so I was able to thank her on my way out. I still smile at the thought of her breaking from her schedule to pop into their equivalent of Sweatshop just to keep her promise to someone she's never met before. What a nice lady!