Hello Elaine. I'm building a database of Gellings and descendants up to the last century, so would be interested in collecting info on this family.
I have John Pearson marrying Margaret Gelling 8 May 1808 Braddan, and 8 children: John, Thomas, William, Margaret, Daniel, Elizabeth, Catharine and August, and that the father was in the Americas at John Gelling's (of Ballamillagyn) 1828 will. He was Margaret's father and grandfather to the children, 5 of whom are mentioned in John G's will as the Executors.

My email is egelling (at) shaw (dot) ca.