Cheers, m'dear.
I also made up an answer to 23D early on, based on the clue, but it doesn't seem to mean anything and I can't find a work by Delibes that fits those letters. I just started looking for characters in his operas & ballets but really.... it's the end of a warm day and life's too short. I'm not going to send this in (I can't because Guardian Java doesn't work for me), so what does it matter?
I'm making progress into the remaining half, so I'll just carry on with that.