Hi Clive
Good to make contact with yet another relation through our common ancestor Thomas Bannan, even though I am decended from his first marriage to Cath Lennaghan.
At this moment in time I think it's possible that Thomas and Cath Lennaghan did come from Ireland, I could find no record of a marriage on the Isle of Man. I also feel that they may have been involved in the fishing industry.
I happen to have a copy of the family tree that you compiled, showing 4 children from his first marriage, there were at least 7.
Regards, Neil