Lady Mary was the younger daughter and youngest child of one of the richest men in the world, Hugh Grosvenor, 2nd Duke of Westminster, and his first wife, Constance Cornwallis-West.

The Duke of Westminster, who went on to remarry three more times, had a keen interest in yachts which helped spark his daughter's own passion for sailing.

She used two Riley Sprites for pre-war hillclimbs, then switched in 1947 to a Bugatti T35; an Alta and Frazer Nash Le Mans Replica.

[3] Lady Mary and her father's last wife Anne inherited 120,000 acres from the 2nd Duke and ranked eighth among the wealthiest landowners in Scotland.

[4] Lady Mary never married and lived mainly at Kylestrome in Scotland and at the Westminster estate in the Orange Free State of South Africa, given to her by her father in the 1930s.