Cryptic crossword No 3,225

There is a history to this puzzle:

Haha that's a lot of stuff going on, which, as ever, I did not spot! Still, lots of delight here: 10a,22a,27a,32a, 2d,8d,19d,26d among my faves. Thanks, PM!

Thanks PostMark for another gem. I solved this over breakfast without much angst though I verified a few of my answers and I couldn't parse 8d and 24d. I had many favourites including 11a, 27a, 6d, 7d, 15d, 17d, and 26d. More in reply.

Your January puzzle was the first I attempted but I was too timid to comment then. Now I can confidently say this is one of the best puzzles I’ve met on MyC. So much to learn from! Beautifully crafted surfaces gilding wonderful wordplay. Some great eye-opening indicators like corrective training 8d, in collision 27a (a noun!), covered maiden 14a, more than you need 24d. As to the theme, I couldn’t get my little finger round it! Faves: 1a, 3a, 12a, 13a, 16a, 18a, 2d, 8d, 17d, 25d. Thank you!