Sharr, I honestly don't think you can do anything about this without falling out with your mother.
What do the parents of your grandchild think of both their baby's grandmother and great-grandmother wanting to be called Nanny?
They might be able to suggest that this is confusing-
Of course, your grandchild might solve the problem by calling one of you nan, and the other nanny or nana.
In your place, I think I would let my mother call herself nanny, as she presumably has done before, and use a different name yourself. There are after all quite a lot to choose from: Gran, Grannie, Grandma, Nan, Nanna, or perhaps make up something new.
When a political leader lies on their CV - can you trust them?





