I have persisted and am happy to give hints. There are some very difficult clues but I am down to my last!! This one I think is a plain clue I.e without any extra letters to put in:
Having poison at police station docked (7) T-N-H-N
Don't know about anyone else but I'm finding this one very difficult ideedc. What on earth it the Iranian city (2 down)? I have ?c?a???a
What is 16 across - starts with G?M.