Across:
   1,27,21ac. "Pieces of 8", you say, done in novel arrangement? (6 5 5)
   4. With passing of centuries, Britain swindle Aussies who shed blood for rich veins (8)
  10. Beginnings of reconciliation easily crushed... ugly rants happen again (5)
  11. I bet Hazel could become 23 of Australia... she opened the 27 21 across (9)
  12. Major nut, zonked out: he left an unfinished 27 21 across (4 5)
  13. He left an unfinished 27 and large mess (5)
  14. Bevis played some percussion (5)
  16. Stir herb mash for mystical experiences? (8)
  19. Straightens up, with new fools taking opening in street (8)
  21. see 1 across
  23. Role deeply embedded in Kafkaesque Englishness? (5)
  24. Favourite passage about 23 11 and the architect completing the 27 21 across (5 4)
  26. Express regret as a pursuit by mounted soldiers ending in catastrophe (9)
  27. see 1 across
  28. Net's gems: strange bits of variety show (many are seen in the 27 21 across) (8)
  29. Game woman marrying around third of August (6)
Down:
   1. Prove jar a safe "retro" container for old city in modern seige (8)
   2. Appointments in House made Cortez group (5)
   3. Loud rants endured after bludgeoning fur seal (7)
   5. It has several layers applied above and below thick core (5)
   6. A partner with pure heart, not in it for the money? (7)
   7. Have Zurich vacation before and after England, and then tour interior China's former capital (9)
   8. As the ball is within grasp, he reaches (6)
   9. Fits poorly... size sure wrong! (8)
  15,24dn. Head for the 27 21 across (near the 1 across 21 down 29)? Yours truly heading at 45° to see new doctor (and love, in time) (9 5)
  17. In love or just set to play in bed?  (8)
  18. Betraying all, let E.T. out! (8)
  20. You do, they say... charming! (7)
  21. Shelter in pergola to south of hospital (7)
  22. Matches unusual lacquers, but not red or crimson initially (6)
  24. see 15
  25. Forward thinking part following ambitious lead (5)