Aha! In 1861 one William Ogston, 19, born Strichen, is a ploughman in the household of an Andrew Massie at Longside and his sister Isabella Massie. That seems to be too much of a coincidence to ignore. And lo and behold, William, aged 29, eldest son of William Ogston and Mary Taylor, is with his parents, and young Andrew M Ogston, in 1871. So I speculate that Andrew was named after his father's employer Andrew Massie, and I have maligned Mary's husband by suspecting him of being Andrew's father.
Aha indeed! That sounds to me like they gave their own names to the census taker, then when asked the babies name said 'Andrew Massie' as in first and middle name because Ogston was the implied surname and the census taker took Massie as the surname.
