A few I know seem to be giving their children a nice name like 'Amelia' or 'Florence' or something but at school and completely universally they are known as a completely different name.
A bit like a Julian Fellowes character. For example Gooey and Tigger or something like that.
In DS's class there is a Philly whose real name is Lydia, that sort of thing. It's quite interesting on one level, and I believe anything largely goes these days. It's curious where it springs from? I assumed Philly was Philomena, silly me!