MiniMoon
I'm a Cumbrian lass too, although I now live in Northumberland. My mother was always called Mam by my sisters and me, but I am Mum to my DD. My DS usually calls me Mother.
As for grandmothers, I had a Nana and a Granny.
We called our grandmother's mother and then the name of the village they lived in or their surname. So I had a Crosby mother or mother S........ .
My DDs were born in N/C and called me mam or mammy. It soon changed when we moved to East Yorkshire they got laughed at for saying it and calling each other man and suddenly I became a mummy.My grand children call me Grandma to my face goodness knows what to my back. I really don't mind.