Across:
   8. Make declaration where declaration may be made (6)
   9. Old eastern end of Singapore, mostly eastern  market (8)
  10. 51 pounds gets everything before start of sale ... motivated seller! (10)
  11. Bryant's 14 part of 20's undoing (4)
  12. Clinks piss Ron off (7)
  13. Waugh's reflective piece of many levels (6)
  15. Revelations ruined 6! (7)
  17. Big and hairy and heading south? (7)
  20. A driver of industry, but issue for Singapore PM? (6)
  22. One that takes the piss as group endure thrashing (7)
  24. Where you might end up if you do as 20 perhaps (4)
  26. GI due for basic instruction (5 5)
  27. Company cast a spell, as 15 6 did (8)
  28. State and ruler sticking together (6)
Down:
   1. Work in East Haiti, troubled country (8)
   2. Singapore's vacation putting the old city-state near the top among cities: 19 perhaps (10)
   3. Flat built mostly outside (6)
   4. President is tosser at heart; he'd happily see you in the chair (7)
   5. Martin kicks a goal, taking small early lead (8)
   6. Good getting out of Asian capital, but not okay for capital manager (4)
   7. Encourage lad who gave senator a proverbially embarrassed look (3 3)
  14. Heart moving platelets may cause this? (10)
  16. Singapore 9 takes time rooting out last pieces of Borneo coinage, and it's not nice when you get caught with them (3 5)
  18. Police set up and broke reputation (8)
  19. Ultimately, if you insist, you steer these paths! (7)
  21. A fixer, councillor eliminated one he owed (6)
  23. Following principle... ultimately this involves a bit of courage (6)
  25. King gets beer and food (4)