Well, Whistler and mother have made good progress, thanks to Drxx nudge on the top line. I confess I used the symmetry to construct most of the grid from the order of the down clues. So still puzzling over the extra letters for some of the across clues despite being able to see what the answer must be. A problem for later.
For now, I wondered if I might have a nudge for 12th clue across. I've tried several lines of attack but they lead to nothing sensible.
Also 12th clue down. Maybe I am wrong to think the last 3 words are the definition. And whilst I have an answer that might fit, there's too much word play for my liking. I expect there's an extra word but I'm damned if I can work out which I should be ignoring. Any small nudge would help.