Arbitrary, "playpiece" does bring back memories, usually of scrounging Monster Munch off my friends because I wasn't allowed a playpiece. Going back to the sandwich definition of "piece", non- Scots may also be interested to know that the filling is often described using "and" eg "a piece and jam", "a piece and sausage". Works for rolls too, hence the sandwich shop on Buchanan St called "Roland Butter"
I've just notice this thread has reignited. Arbitrary, if you are still out there, would that be a downloadable content set that is available on Sky Anytime?
I don't think we had a name for our school break snack, it was just "What have you got for break?". Mine was either Ryvita and Marmite or (gloriously,on Monday) a dripping sandwich (a smear of beef jelly, then dripping with a sprinkle of white pepper on thick, white crusty bread - now that was a piece.)