My grandfather is known by a nickname that has nothing to do with his given names. His mum named him Herbert James while his father was away (at war I think) & when he came back said I'm not calling my son that, we'll call him Joe. He's been Joe ever since.

I don't have remorse about DS's name or my own, although I like to be called a shortened version of my name, but find it difficult to introduce myself by the shortened version if I'm giving my surname.