Thanks Chrise & Jono. You nudged me towards the PDM and you are right I did kick myself! Very good CW overall.
As I come from the area 4d was easy for me though 22a was not familiar to me - seems it's a word that's only used in a particular type of school? 22d was a new word for me, as was the non-animal meaning of mole, so Google was required once I'd guessed the homophone. Saw an exhibition of 23a's work at the Tate Modern a few years back (in the days before the plague, it seems an age since such things were considered normal!). Thanks to all, including Paul.