Across:
   8. National terror group with TV show (5)
   9. Force field broken with ring destroyed in 27 where 12 Bay 17 across founded by order of 26 14 in 1824 (9)
  11. Stores sold rare assembly, but with ring missing (7)
  12. Island and bay in 16 for major, or famous, English school (7)
  13. What you get dividing whole numbers with others, as worked in art also (9)
  15. Wrongly quote "beanie" as from Canada (5)
  17. "Gulag" writer and medical specialist between them melt Tesla while reversing (5 10)
  19. State's capital, young at heart (5)
  20. Fish one caught, new as it happens (9)
  22. Icon Victoria holds to be crook? (7)
  25. Bullies Simpson back inside, laces knotted (7)
  27. Rewrote line as pun for land almost all at sea (9)
  28,1dn. He commanded the 22s building the 12 Bay 17 across, revelling in merry hell (5 6)
Down:
   1. see 28 cross
   2. Oddly mean, U.S. Rail train rival in African country (10)
   3. Type of sentence seen in sad file (4)
   4. Brother is scourge of 16 capital (8)
   5. Every second weed brought up identical swellings (6)
   6. Insult rulers turning up after queen left (4)
   7. Put returns back with a couple of bondage items? (8)
  10. see 23
  14. see 26
  15. Create ethereal piece for oral presentation (5)
  16. Victoria's plot in another state? (10)
  17. As the artist, was formerly known as restricting intellectual property in African island (8)
  18. Crazy nut actor an unreliable fellow (8)
  20. Flout recipe after page one making quantity of soup? (6)
  21. Writings some academes say significant? (6)
  23,10. Fan not prepared for Spratt's sort of diet (3-3)
  24. Poles first fashioned as bars (4)
  26,14. Famous premier of 16 has laughing gas and gets oddly leery for old Surveyor General of N.S.W. (4 5)