I guess it not only happens in Scotland. My Grandmother's name was Martha Harriet, her family in England called her "Pat" and my Grandfather called her "Jane". Go figure!!! I would suggest process of elimination. If you can find out anything about either one of them for sure, then you could be fairly certain that the other one was Polly. Sometimes dates, other relatives, addresses, etc. can be a help unexpectedly. gretchen Michigan USA