WILLIAM JAMIESON was born c.1741. (From headstone inscription)
Martinholme is a fairly unusual name, and there are only two Margaret Martinholmes born in Avondale in the OPR index - 16th of September 1753 (to Gavin Martinholm) and 22nd of July 1755 (to James Martinholm). In typical Avondale OPR fashion, the mother's name is not given.
William Jamieson married Margaret Martinholme in Avondale on the 5th of December 1776. (Transcribed from OPR)