Thank you Neveracrossword. For the first time I can remember, I am actually able to say "Yes, it's a terrific clue" and do so with humility. For a setter, the words 'terrific' or 'brilliant' tend to apply to cases where an intractable-looking answer has been very carefully and painstakingly pulled apart and assembled in an original, witty, smooth and (hopefully) concise clue.
This answer forced itself into the grid because of checking letters and, as I wrote it in, I didn't know what I was going to do with it. When it came to tackling it, the two wordplay components and the definition just jumped out. Really - can't have taken more than about 30 seconds.
That's how it goes sometimes. You can spend half an hour devising a clue that's 'OK', and no time at all in spotting something memorable. Luck of the draw!