Can't really help with the history of the family going back, but i think we're related. ;)

My maternal grandmother was Myrtle Joyce Gilmore Shooter, born to Alfred Ernest Shooter & Katherine Laurina Mary Cahill. I have a sneaking suspicion that she was your Gran's sister. I'm sure that i remember a Aunty Hilda at the Christmas Day Afternoon party's at Uncle Freds.

Contact me if you want any further info, i can link you to my ancestry.com family tree