Complete
00:00:00
7 14 19 1 9 12 21 2 15 3 11 20 10 4 18 16 5 8 13 6 17
  1. 1a Large tuba used in marching bands (10)
  2. 7a Vehicle seen between holes (4,4)
  3. 8a Make a loud animal noise (4)
  4. 9a German idealist philosopher, d. 1804 (4)
  5. 10a West Indian dance music (7)
  6. 12a UK's prerogative of mercy (5,6)
  7. 14a Wimp of a whiner (7)
  8. 16a Percussion instrument with acoustic chamber (4)
  9. 19a Elementary particle (4)
  10. 20a Boiler suits (8)
  11. 21a Narrow tube through which pellets are blown at a target (3-7)
  12. 1d Standard — cattle (5)
  13. 2d No laughing matter! (7)
  14. 3d I'm afraid to say (4)
  15. 4d Will's Anne (8)
  16. 5d Anxious (5)
  17. 6d Clergyman (6)
  18. 11d Shifty dodger — bossy lot (anag) (8)
  19. 12d Curio (6)
  20. 13d Inactive (7)
  21. 15d Moulded ice cream dessert (5)
  22. 17d Middle-distance runner, like Roger Bannister or Hicham El Guerrouj (5)
  23. 18d 0 (4)