21a So bowled over by a Sicilian lover (4)? - c - s. 33d Composer arranged a march in thirty days (11)? ends in n - v I think. 39a Supporter of president expressed irritaion, that's manifest (8)? - a - l - i - -. Perhaps these can kick-start my brain. I realise everyone has gone back to work. I'm still catching up on yesterday, always one day behind myself..
Aha! Great, thank you pbeach and dear dependable LiK. How I couldn't get Rachmaninov is a disgrace - I actually said 'piano concerto' to myself and even hummed the tune.