Called Secret a bar often referred to using Shredded wheat to describe what it looked like. First made by Rowntree (now owned by Nestle) in the late 80s (confirmation needed).
From post of user 'WillieWonka': Production of Secret bars stopped about 1996. Complicated process to make them -chocolate "shredded wheat" bar with a fondant centre. Plant was scrapped / sold off when production stopped (not a big seller) so no chance of them coming back. Too sweet and sickly for me anyway. A bit like a giant Walnut Whip with no walnut, lots of fondant centre and not much chocolate. Having said that I love Walnut Whips.