I think someone told me that Waitrose might have been carrying them. One of our members's partners works for Waitrose. That was at least a year ago though and I'm not sure it's still the case. Even so, with things like that, not all of the stores will have them (they live in an area with lots of Americans). And Waitrose is not really nationwide.
So in general, as Kaylesh says, the answer is probably 'no'.