This I think relates to families referred to in postings by Beppy & Hursty52 above.
My ancestor is Marion Graham (I think born c. 1815, Carnock). As far as I can establish, her parents were William Graham and Marjory Taylor. From reading this thread, I am guessing that Marion's sister was Janet (who married Andrew Robertson, per above).
To help confirm it is the same family, would anyone be able to advise if Janet had a sister named Marion?
Unfortunately, I have no other information yet on the Rev Taylor (Marjory's father), though I've seen his specific reference on Marjory's death certificate.
Thanks
David