The traditional Mastermind match for the best losers from the first round takes place tonight at Liverpool University, in this fourth and last of the semi-finals. The contenders come from Merseyside, Bolton, Manchester and York - a truly Northern occasion. The contenders are: Jolyon Coombs, stage manager - Commedia dell'Arte Rosemary James, teacher - Life and works of Frederick Rolfe Frank Lynch, teacher - European history, 1900-1945 Anthony Martin, librarian - Greek mythology