Hi Sarah
Your great-grandmother is my grandmother - Margaret Lord (I think middle name was Davidson?) 2.2.1895-17.2.1980.
Information from research of Margaret & William Craik (my aunt and uncle - your great-aunt) - Margaret's father was William Lord, 1871-1926, had 9 siblings. Their father was Thomas Lord, 1839-1912, and his father too was Thomas Lord. Does this tie in with your research?
Would love to talk further if possible. (I am a daughter of your Great-Aunt Henrietta / Bunty.