Cadbury's Fudge was (is) a stick of fudge, covered in chocolate. Very simple and very tasty. The ad I recall involved kids coming out of school, and one is met by his mum who gives him a Fudge bar. The song was: "A finger of fudge is just enough to give your kids a treat. A finger of fudge is just enough until it's time to eat. It's full of Cadbury [or possibly "natural" ??] goodness, but very small and neat. A finger of fudge is just enough to give your kids a treat."
The package was orange with a pale swirly design, and purple lettering. Definitely one of my favourites as a kid.