These are flat CDM bars with 'puddles' (raised miss-shaped domes) of runny filling. The best one is mint, but there is a hazelnut one too. I feared that the chocolate would be nasty, following Cadbury's take-over by Kraft, but actually it's just like normal CDM.
They are only available in a largish bar, and lots of supermarkets are selling them for £1 instead of about £1.60.