Paul Rogers had starred in the original London production of the play in 1962, but in the role of "Reginald Kinsale", not "Sam".
Robert Brown had also been in the original London production, but played Sam at forty, not sixty.
In stage productions of Peter Ustinov's play, Stella is usually played by the same actress at all her different ages (it was Diana Wynyard in the original London production and Eileen Herlie on Broadway), but here, in this TV production, she is played at different ages by different actresses.