Across:
   7. Complicated once Asia loses southern region including Australia (7)
   8. Neighbour Nicky, like her grandpa Marcus, carried by Brownlow he landed (6)
   9. Where group works us out with attention to detail (6)
  10. A Japanese group shit a Chinese group! (7)
  11. Musician doesn't want to be inside a furnace (4)
  13. Oddly, total scorn for singers (10)
  15. It comes out of a car tire (7)
  16. American turning blemish into guitar feature (7)
  20,8dn. Defeat at sculling? (5 2 3 5)
  23,27. Group being profound and unblemished with recording comeback (4 6)
  24. Log producer starts to dig in and raid its smaller trees  (7)
  25. see 28
  27. see 23
  28,25. Strong Ellison composition for a UK group with a mobile 9 (7 6)
Down:
   1. Mourn Tex, destroyed where 6 disaster happened as described in 20 8 down (8)
   2. see 4
   3. Bill's in song's prominent parts (8)
   4,2. Guitar part in 23 27 recording (7 4)
   5. Coffee is sometimes breaking cheaper cola tedium (10)
   6. Better place for fiery 12 concert? (6)
   8. see 20 across
  12. Musician's loud nasty shock with power amplifier (5 5)
  14. Rejections set back young lad (3)
  15. Units used for gemstones (3)
  17. Implements adaptation of Len's suit (8)
  18. Adaptation for big screen mostly would have been worth avoiding for Titanic, etc. (8)
  19. Height of King in bronze? (7)
  21. Unfortunately, die not speaking about one reaching the other side (6)
  22. Rust perhaps hard to get out of bullock skin (5)
  26. Leave out nothing with German (4)