This answer would be more easily found by contacting the Cadbury website. I'm sure this will come up if you put 'Cadbury' and 'chocolate' in the Google search engine.
Not enough!!! They should make Aztec bars again. Was that Cadburys or another firm? Anyway, they were wonderful. There are probably loads more that I loved when younger but can't remember them now - just Aztec that sticks in my mind as I bought them by the barrowful (not literally, but you know what I mean!!).