Overview: Magnus Magnusson tests four more contenders in the Debating Chamber of the Oxford Union Society. Contestants: David Watts (Royal Navy officer) Elizabethan theatre; Indrani Hettiaratchi (teacher) life and works of Frederic Chopin; Roderick Diggins (clerk) English royal palaces, 9th century to 1912; Alan Colby (local government officer) life and works of Francois Truffaut.