Kath, here is what I have on these Buchanan's, William Buchanan, grandson of Thomas of Carbeth, bought Ardoch in 1683, his grandson John married (first) Mary, dau' of William Crawford, merchant, Glasgow, by whom he had Thomas b.1733 and other children; (secondly) in 1747, he married Elizabeth dau' of William Buchanan, writer, Glasgow, by whom he had a dau' Frances who mar' John Maxwell of Dargavel, writer, Glasgow and had sons John & William, both in turn, Lairds of Dargavel. Thomas Buchanan was thrice married. By his first wife Margaret, dau' of Moses Buchanan, he had John his successor, b.1761. He was succeeded as a partner in the Ship Bank, by this John who married Elizabeth, dau' of John Parks of Netherton, Worcestershire, by whom he had John, who sold Ardoch; Mary who mar' Robert Finlay of Easterhill in 1810; Margaret & Elizabeth.
Thomas received an award of four guineas from the best dozen of felt hats, from the Edinburgh Society for Arts, Sciences & Manufactures in 1757. A writer is of course a lawyer. Mr Buchanan was MP for Dunbartonshire from1821 to 1826. Skoosh.