Across:
   8. Missile Siam used to defend territory (7)
   9. Oddly, Booth deems it Abe's leadership making country now defunct (7)
  10,6dn. Organisation dissolved in 1918 humanitarian purge rose in new format (6-9 6)
  11. Ancient land lost hope in turning over foreign spies (9)
  13. Desperate need for mythical land (4)
  15. Beginnings of dirt... unto such finally revert! (4)
  16. Set fee for soft staple (5)
  17. Ancient communication found in dinosaur dung (4)
  21. see 7dn
  23. Giant squash production involving bizarre act (9)
  25. Deranged Nazi chokes vocal representitive of 9 perhaps (15)
  27. He had a number of about 602214085774 trillion drop right out, losing gravity to light-speed green matter (7)
  28. Country areas move in mysterious ways, entirely pointlessly (7)
Down:
   1. Bear loss of arms, loss of ear, loss of far flourishes (8)
   2. Eastern leader slain in terrorist sarin attack  (7)
   3. Some did as he 8 down (4)
   4. Lots and lots of a hairstyle - bobs perhaps (10)
   5. He acted unfairly and broke the rules (7)
   6. see 10ac
   7,21ac. 12 down perhaps hands joint around - not the end of the world! (5 4)
   8. Broken mast, deep trouble, panic! (8)
  12. Weep about hospital distress call to head of Morals in church authority (10)
  14. Hear unit moving into eastern 25 region (8)
  18. Fret and grieve on losing leaders, or get back? (8)
  19. Learn about taking tricks - how leads hold the attention (7)
  20. Traumas devastated eastern land (7)
  22. Poached lion, to eliminate the odd wild cat (6)
  24. Fight for morsel (5)
  26. Resistance working for the crown initially (4)