Hello, TrishI
Sarah Murnin was the elder sister of my grandmother Elizabeth (Lizzie) Murnin. I have very little information on Sarah's husband, but have some very reliable information about their descendants. They had seven children: one of them, Sarah ("Sadie") Gilmour and Alexander Dalrymple had six of her own, while James Gilmour and Dora Lish had two daughters. Patricia Ann, one of James's daughters lives in London and has been working on her family tree for some years. The other, Kathleen, lives in Western Australia.
As teenagers, my mother Margaret ("Peggy") Peat and her brother Andrew were quite friendly with several of the Gilmour children, especially James, Peter, and Andrew.
Do you use Ancestry.com? If so, you could see my tree (the WILLOTT tree) and we could exchange further information.
Dominic Willott