I’d never heard of it either, but a web search finds a Wikipedia article, a few pictures and the implication that it’s not sold in the UK.

Also, calling Cadbury “British” these days is a bit of a stretch. Yes, they were founded here and are still headquartered here, but they’re now a multinational corporation owned by an American corporation.

And despite that American corporation being run by a Belgian, the quality has definitely gone in the American direction.