Our Morrisons carried Reeses peanut butter cups for a little while a year or more ago, then not anymore. Haven't seen them in other grocery stores, but haven't been looking either.
I can usually get them at a sweets shop down the street, or in our deli though.
The big ones, not the little ones. I do like the little ones! (and the big ones)
Morrisons does usually have the Nutrageous though - is it good? I've never tried one.