Couldn't swear by it, but I seem to remember seeing them (or a similar brand) in the American section of the Tesco on Maryhill Road in Glasgow. (We've had pizza from Dominos that when it says it's got chorizo on it it tastes very much like SlimJim.) Hope to be over there in the next couple of weeks, will try to remember to look. It's not on their website, but they have stuff in there sometimes that isn't online.