After my hour was up had eight unsolved so looked them up.
I'm not convinced by the Spoonerism at 20a. Surely part of the second word is pronounced like "un" but to make the Spoonerism work it has to be pronounced like "eau"? (Hope that's not giving too much away) . That said I think I last solved a Spoonerism about five years ago -I never see them.
Can't see the investments in 12d
For 13d I thought a hunk of meat was more like a shish kebab than the answer.
Not very gruntled overall .