Sir Curtis and Harry Lewis have 4/- (four shillings) paperback copies of Jason's novel "Index Finger Left Hand" (confirmed as a Mark Caine tale in The Man in the Elegant Room (1969)). Another is "Dead Dames Don't", known simply to its author as "DDD".
Stewart's Interpol/Department S ID states his height is five feet six inches, and his weight 150lbs.