Stuck on a few today...... 12 Across - Bates has cleaned Byron out (7,5,), 18 Across - Ulcerating insect caught behaving irascibly (12), 10 Down - Locate tail movement on vehicle (7,5), 13 Down - Help in hearing premature change to Tosca opening (3-7). 14 Down - Airport requires gradual overhaul - road up (9). Any help will be grateful.