Across:
   1. Performer with flowing garment and odd bits of rite, drawing energy from orb (6 5)
   9. Large fellow who founded an empire (5)
  10. Appeal of core trio's image: kinetic, charismatic (9)
  11. Sonar rat originally possessed, which used sound to tell what was going on (8)
  12. Yanofsky found around end of the index (6)
  14. Chance to showcase singing in variations (4)
  15. Name of it I'd refine carefully (10)
  18. Molten lead frying biscuit (10)
  19,2dn. Leader of beat with honourable members either side in music session (4 6)
  21. Denounces loss of lair for ancient masses (6)
  23. Disables "Backspace" after key named "End" initially (8)
  25. I get hit, he gets hit, we should all get a party for this (9)
  26. Queen may mind one swapping (5)
  27. Group went ahead of Count Ferdinand's vehicle (3 8)
Down:
   1. Fixed error I made losing love? (9)
   2. see 19ac
   3. Forcing through arrangement, grand or dim (10)
   4. Quiet time ... it's for reading perhaps (4)
   5. If I tire, pay off fringe characters and take the rest back for a drink (8)
   6. Illusion that band was cheap one (5)
   7. Lennon-McCartney joint singles a musical success (4 4 5)
   8. 27 performance creatively minting orgasm (9 4)
  13. Junior appointment in badly rent vessel (10)
  16. Is it a loon's torment? (9)
  17. Time invested in alternative cafe "Fed With Air" (8)
  20. Wonderfully brave and ultimately pivotal attack (6)
  22. Farage has country changing sides (5)
  24. Townshend's favourite, Entwistle's first (4)