Of course, the
PENGUIN is really a
biscuit rather than a chocolate bar ... made (unless I'm very much mistaken) just down the road from Billy, in Carlisle.

Yet another of the nice things about them is the "Christmas cracker" type question and answer on every wrapper.
A bit like my other favourite:- the Animal bar (yes, a real chocolate bar, that one ... sized [and priced] for kids' lunch boxes) - where you will find a puzzle on the inside of the wrapper. The trouble there is that many people just chuck the wrapper away (usually straight onto the deck, by the look of things) without realising what they are missing!