Chair mystery

If, as Irvine Inglis claims (Letters, 21 April), negotiations for "final peace" between England and Scotland, in the reign of Robert Bruce, included the return of a coronation chair and the Stone of Destiny, why, may I ask, is there no mention of a stone and chair in the Treaty of Edinburgh-Northampton?

Imlach Shearer, Carslogie Road, Cupar