What do your grandchildren call you?

My grandmothers, in an industrial Lancashire town, were Nanna on my mother's side and Grandma on my father's.

I don't have grandchildren (does that make me a fraud here?) as my daughter, now 40, has shown no maternal tendencies. If I did I'm not sure what I'd want them to call me except that I really don't think I'd encourage 'Gran'. But that's just me.