Across:
   8,5dn. Visual tone of America: a motorist takes lap of waterway (8 5)
   9. Old author brought back Thai as Indian limited (6)
  10. Village post office hosts nasty blue  (6)
  11. Oddly, fur gets chilly in recent times (7)
  12. Not usually first, but the last in rush to a blue (9)
  14,7dn,18dn,26dn. Senior figure, Washington, gets any on wild plain to rank a reserve around 8 5 (5 6 8 4)
  16. Exceptional son amazingly taller (7)
  17. Take time out at a fancy hotel on a patch of America (7)
  20. Teach of talking horse, if unknown (5)
  22. Mix one into rotting food with last of ale (9)
  24. It blows from 21 with no volume, or is turned around (7)
  25. Transfer device fixed in shop (6)
  27. Creative cure is holiday on 5 perhaps (6)
  28. Mal-born, a-twisted? (8)
Down:
   1. see 18dn
   2. Place where dead are taken to doctor? (4)
   3. They are admired in 14 7 or in hats (9)
   4. Essentially ignored by people, sort of pine (7)
   5. see 7ac
   6. Easy money to be had in new ships craze (4 6)
   7. see 14ac
  13. Iron facial treatment for 17's neighbour (10)
  15. When kneeling, you might be in favour of sitting (9)
  18,1. Teddy declared 14 7 one-nil - no amount meant redevelopment (8 8)
  19,21. Issue with conjuctions - trees destroyed in 17 eco-system (7 6)
  23. Cares about land  (5)
  26. see 14ac