Across:
   8. Part of Australia or America? (NB: erratic part!) (8)
   9. Rock turned up by small animals (6)
  10. Third of cabinet don't have courage for bans (10)
  11. Concerning, casting aside love to make border (4)
  12. Protective shield raised when mare tangling with bull (8)
  14. I'm sad about your leader being a disappointment (6)
  15,4dn. Feature of 8: aged, ordinary, trouble-spinning fellows, but with application (3 10 5)
  16. Satisfy beast, bringing food (7)
  18,1dn. Old Brisbane track trainer or old Melbourne train tracker? (3 4)
  21. Range is rare formation (6)
  22. Numerous (not a hundred) cement dwellings together in a group, generally 27 (8)
  24. Heartless, 22 offers temporary accommodation (4)
  25. Among batches of residents, in general indigenous, naming ancient local roots (10)
  27. Let first one out, happy (6)
  28. Lee's the less upset about end of tour (8)
Down:
   1. see 18 across
   2. Battered cub with sore hide (7)
   3. Relating to one's mob, having bowled in test (6)
   4. see 15 across
   5. Events arising from long stories, poetic tales without poetic conclusions (8)
   6. Where you'll find consul, attaché and secretary embarrassingly ignoring every other trio (7)
   7. Job for type of 19, such as the 25 24 26 at 15 4? (10)
  13. Some supersede pill, implanting revolutionary bugs (10)
  17. Signs of 19, in a way, in macabre trophy being raised (8)
  19. Where people might shout back from the outset, or parade (7)
  20. I'm getting what everyone wants a slice of: hollow, tawdry worldliness (7)
  23. What those around hear, one within smells (6)
  26. Race? It's all about land! (4)