Across:
   1. Study of regulatory systems developed by CSI centre  (11)
   7. People in software (3)
   9. House and ground which have 20s (5)
  10. Grasping both hands, feeling fainter as more beset by miserable weather (9)
  11. A rum China arrangement... beware the candidate from there! (9)
  12. Outcome of coin toss, with you in Europe flipping (and turning), is ethnic demarcation for African (4)
  14. Rogue editor, surrendering nothing, taken to court (5)
  15. You're doomed if your days are hiding order under chaos (8)
  18. Afterthought changes religious books (8)
  20. Some suggest it lends status (5)
  23. Crowd going off when trio playing (4)
  24. In dream, I comb erotic leader of 2 during 5 (9)
  26. Garam masala and raita has one wanting a drink (9)
  27. Outcome of coin toss, with you in Europe flipping (and turning), is ethnic demarcation for African (5)
  28. Most common word, not turned into any other? (3)
  29. Tragic chapter, as to upset on grand scale (11)
Down:
   1. Disaster, one interrupting peace: it precedes end of humanity (8)
   2. Only secondly about 12 or 27, and firstly defined by one's country? (7)
   3. Heeds cruel abuse, getting put off (10)
   4. Toughness under cane thrashing (9)
   5. Great 1 down, 28 29, 19 of 2 as backward, somewhat Nazi killing? (5)
   6. Magnitude of some outsiders accepting part in 5? (4)
   7. Tax time ... put shit on "farm" vehicle! (7)
   8. Chamber sat without leader (but with one in spirit) (6)
  13. Write controlled and mostly terse lines of poetry, often using this (10)
  16. For band members, total return in cash is a negligible salary initially  (9)
  17. Comedic one gets guts turned in vast evil tragedy (8)
  19. Bravery one lost after second horror (7)
  21. Tee is where to put star at Christmas? (7)
  22. Quick progrom wiping out 2-4 percent heartlessly (6)
  24. Love getting into fine spray, just a little wet (5)
  25. Inclined ones going for white powder (4)