One Two was a sort of Twix deluxe - twin chocolate bars with a biscuit filling. Unlike Twix, the two bars were individually wrapped with a serration between them. I even remember the advert: a mock gameshow where the object was to see how long you could go between eating the first and second. I actually used to take up this challenge, but usually lasted no longer than about 30 seconds. Surely someone must remember these...?!