Across:
   4. Captured in two notes (3)
   8. Once more inflict awful poem, sire? (8)
   9. 8 direction so lost in broad domain (6)
  10. Reptile returned with tail removed by British sort of nut (6)
  11. Gateway takes couple from Uganda to another country (8)
  12. Variation of amounts in range (9)
  13,20dn. On radio, I jeer about 16 across state of 10 being supervised by a monster Jesus (3 2 7)
  16. Disease treatment where you inhale salty air (7)
  18. Many thousands of 21s perhaps die... grab treatment! (7)
  21. "Platoon" lacking model from the East (5)
  23. Typical ways of arranging a map's grid (9)
  26. Repeat, as not the same not the same (8)
  27. Xi Jinping's tag has so many letters! (6)
  28. Unusual detail of unicell? (6)
  29. Dangerous animals startle badly on runs (8)
  30. Essentially Salvadorian commotion (3)
Down:
   1. How deterrents should be made more safe (8)
   2. Warrior, dame, nazi and monk all getting naked (6)
   3. Game played for holiday I missed (9)
   4. Wild apes 4 across 15 (7)
   5. He comes up among leaders of new republics (usually) (5)
   6. Carrying on with Top Gun is awful! (8)
   7. Something helper ran doing? (6)
  14. Observe key enemy holding (3)
  15. Military force made man master (9)
  16. Observes Italians holding position (3)
  17. Regulars in Asia coup value loot in 16 across state of 10 (3 5)
  19. Party member rode roughshod, but he was the leader for 9 of 10! (3 5)
  20. see 13 across
  22. Regretting short sharp dismissal under new rule (6)
  24. Principles of refined ladies? (6)
  25. Oddly, beach vital for 16 across state of 10 (5)