Fanarg

I've checked a few grocery stores (sainsburies, waitrose, whole food, and some local grocery stores) and a few convenience stores and stuff like that and can't seem to find it anywhere. I'm looking in the condiments aisle next to the other hot sauces like tabasco and red hot, should I be looking in another aisle or am I just looking at the wrong stores?

I'm living in Kensington, so keep that in mind when giving suggestions, I don't mind traveling a bit, for instance I imagine some store in Piccadilly must have it, but which one?

And if you have no idea where to find it, suggestions of where to find cheap alcohol, good pubs, and other fun stuff is just as welcome.