Not sure whether it's been mentioned already (I did a search and couldn't find it) but there is a mistake in the clue to 21 across. The answer is Faure but he did not write Clair de lune. Debussy did.
Well I never knew that! Thanks for the information. I am very embarrassed now as I am a music teacher but have honestly never come across Faure's Clair de lune before. I'm going to have to investigate that.