All done. I went for the 8 in the artwork. A couple of queries and a little niggle.
12a I can see some but not all of the wordplay. I sort of get it but.....
15d I have the answer and the definition but can't see the wordplay.
20d I'm not convinced that the larger part of the solution is synonymous with the relevant part of the clue. I can't see any confirmation in Chambers.