13A - Catherine was such a big wheel (7) I have T???I?A
15A - sort of prose by which one may be swayed, we hear (7) I have S???I?E
14D - a preposition bad to end a sentence with ? - a rule up with which Churchill would not put, yet which some writers may ___ ___ (5,4) I have ??R?E?P?N
16D - Athenian spiritual brother of 1D (1D is Thersites) (9) I have ??????T?S