Across:
   1. Dressing up his "nimble" leg (broken!) (12)
   8. Unusually rearing? (7)
   9,11. Drunken reel, streaking part of Irish 27 21 (7 6)
  12. Clay trap - cool mob oddly don't leave here (8)
  14. Among hundreds I follow musical drama as performed in theatre (10)
  15. Technology should all be this friendly... development needed for sure  (4)
  17. Mighty embrace with energy (4)
  19. Hen gains an eccentricity mischief (10)
  22. Mares put to work in difficult direction (8)
  23. see 3dn
  25. Went back to later shades, not so dark (7)
  26. Los Angeles medium initially imitates a nomadic East European (7)
  27. Study text - one on press-ganging (6)
Down:
   1. Fatten and behead hen... King wanting second piece (7)
   2. Cricket gear made from novel material gets negative review (8)
   3,23ac. Hero of Nazareth from France and Viceroy of Ireland from England who alleged support of Germany from Ireland (4 6)
   4. Seeding rain in grassland region selected for deep absorption (10)
   5. Where to put fliers, being somewhat less than garbage (6)
   6. Worried over sun storm (7)
   7. If Lord Mayor of Dublin be living there, building home is an onus!  (7 5)
  10. Tangled, then brainily intertwined (12)
  13. Mac, perhaps Hal, herding characters? (10)
  16. Super Mario racer made it a trend (8)
  18. Secret police pages to get shredded (7)
  20. Nice chap gets one an alpine beverage  (7)
  21. Key juncture I criss-cross over (6)
  24. Friend comes back following loud commotion (4)