Thanks to Jono (post 15) for a pdm re 21a. It was driving me mad reading all those posts saying how brilliant it was, when I just couldn't see it! Thanks also for help parsing the second word of 1a.
Favourites were 13 and 17a. Also liked the Primarily in 15 (although, strictly speaking, I think she only had one?!) and, for once, thought the spoonerism was a good one!