I was doing some research for a lecture I am delivering on language, culture and advertising. I came across some pics of old 50s sweets and among them was a box of sweets that had a hard shell and chocolate centre and they were called Cabanas! They were made by Cadburys too!
Also seen was a Frys bar called Punch. Now, I think these were available in the 1960s too but were discontinued in the mid-late 60s. I have a feeling they were fudge filled but can't be sure.
Also saw a Cadbury's bar filled with pineapple cream.