Plot: Another finalist in Mastermind 1981 is chosen tonight as four more winners from the first round pit their wits against each other in the Debating Chamber of the Oxford Union Society. Godfrey Abbott (ordnance surveyor): Railways of Wales Leslie Grout (schoolmaster): Burial grounds of London Iris Henson (research student): Life and works of Gilbert and Sullivan John Watt (lecturer in computing): 'Flashman' novels of G