Toy Robot 1970's

I've been searching for a particular robot , I think there was a series of 3 bodies sold in the UK but can't recall their models name or manufacturer. They were sold separately in a plastic display unit , made in the 1970-1973 The robot  moved via a caterpillar track system powered by 2 AA batteries in their legs. The robots were able to rotate their arm and would snap forward to allow a missile to be launched.The small electric motor was also detachable from the section containing the tracks. Does my description rings any bells. Steve