Thanks for the welcome, Mick.
I've been lurking off and on for a while but never posted before today. I'll definitely take a look at that link for future look ups.
Yes, I think you are right about Mary/May being one and the same.
Joseph's family live in and around Gateshead, Newcastle in NSW. An area whose main industry is mining, so the family didn't move far from their roots despite being across the world.