Thank you for the responses to my request so far.

You have confirmed the background to Rosa and Husband.

I am being drawn towards the marriage of Henry Thomson being bigamous, a marriage to Isabella Bowle a lady of the same age as his eldest daughter too.
From the point of view of Isabella, Henry would have provided a name for her son Gordon a name I know he and his descendants use.

The search for Rosa goes on!!

Many Thanks

Norman E