Douglas Richardson in Magna Charta Ancestry gives the wife of Richard Vernon, son of Richard Vernon and Juliana Pembridgge as Joan Griffith daughter of Rhys ap Griffith with a marriage date of 20 May 1380.

The latest Haddon Hall booklet with introduction by the current 11th Duke of Rutland, gives the wife of this Richard Vernon as Joan daughter of Richard Stackpole. Richardson says the mother of Joan Griffith was the Stackpole.

Does anyone know which is correct?