Well I've filled in an answer to every clue, but it has been difficult and I've lots I can't parse. Thank you to Geeker for your Spoiler. I'd never have got this without your spoiler. And thank you to everyone for the other hints.
Answers I can't parse completely are 4ac (the middle letters), 12ac (the second word), 19ac (which is the second word), 24ac (the first four letters and the last three), 2d, 13d, 16d, 20d and 22d. I've just noticed that I haven't got 23d, so that will be my LOI.
My FOI was 1d, my COD was 8ac
I found this really hard and not at all pleasurable. But no doubt I'll try again next week. I'd never have finished it without the help here.