The sitter was the daughter of Sir Alexander Anstruther, subsequently Lord Newark, and his wife, Elizabeth Price, the daughter of a captain in the East India Service. Sir Alexander Anstruther was the third son and eventual heir of Jean, Baroness Newark and her husband, Sir Philip Anstruther. The Hon. Jane Anstruther married John Sanford of Nynehead and by him had four surviving children, she died on 8 January 1790.
David Mannings has suggesed this picture dates to the mid-1770s.