Solution to 2151: Sources
The three theme words are CHAMBERS (12A, 16A, 40A), OXFORD (colleges) (24A, 4D, 8D), and (works by Wilkie) COLLINS (9D, 13D, 30D), each a publisher of a DICTIONARY, which needed highlighting. First prize Peter Cramb, Bridport, Dorset Runners-up Jane Howard, Chilham, Kent; L. Coumbe, Benfleet, Essex