Had a good few weeks without needing any hints - however finding this one a bit tricky - 3/4's full grid and believe I have all 7 clashes, however (all have an extra letter in thematic part):
23a Plant ecstasy in path of policeman (4) - answers to crossing clues give BTET so something wrong somewhere
14a Old regime abandoned allegiance (8) L?E?????
21a Clever nurses Prince inspired at first birth (8) N?TAP???
Hints or direction sorely appreciated.