Excellent, thanks to Picaroon!
Also a bit confused by the wordplay in 4a, but the sheer number of delightful clues makes up for it: 10a, 11a, 21a, 23a, 26a, 2a,8d, but for COD I’m going for 25a because it caught me out fair and square dismissing a possible way of solving it on first reading.
FOI 9a, but only after I’d read all the clues once. Solved in 3 little bursts.
Definitely one to enjoy.