OK, I solved all the clues, but later decided to have a look at this forum to see if there were any interesting comments. I thought I had parsed 12a, and thought it a terrible clue, but various comments here seem to be hinting at a differrnt (and I hope better) parsing, which I can't see at all. Any really strong hints, anyone? (I'm not usually one of Paul's greatest fans, but I really did like this puzzle. For me as for many others 17d was both LOI and COD. A really excellent clue.)