I recently found one of my ancestor's wills which is on free download from National Archives Discovery now. John Mackmin, London, 1775.
Part of the will is "much honoured father John Mackmin of the Parish of Maybol in the Shire of Ayr "
John junior was born around 1750, as indicated on his marriage to Elizabeth Sumner in 1771. I'm trying to find his birth record but there seem to be none fitting with Maybole around 1750.
There is a John son of John McMin New Abbey 1751, 60 miles away and a John McMin marriage to Margaret Narin Kirkcudbright 1749.
There are no real matches for Mackmin on Scotlands People.
Any help gratefully received!