Across:
   6,15. Vacant land where run lies? Ultra-nonsense! (5 7)
   7. Right to occupy should be based on skin? Polar opposite! (8)
   8,13. PM akin to plague, rampant and without love (4 7)
   9. In 7 down 17, home of mermaids? (3 7)
  10. 13 for example smart with land (8)
  12. Kind widow most regularly features in popular talk (6)
  13. see 8
  15. see 6
  18,26. Fixed it: I've latent possession, recognised by 24's case (6 5)
  20. Bonus that is sought primarily - some 18 peoples have secured these (8)
  22. Opponent of 24's landmark claim of New York district land (10)
  24. Through activism, aborigines found a hero (4)
  25. Communist perhaps abandoned by the majority (8)
  26. see 18
Down:
   1. Grows illegal lopped triplets off behind screen (6)
   2. Partly hand back map left in 7 across Island community (4)
   3. Make up farm vehicle - copper not able to catch it to begin with (10)
   4. Can trace family in black and white? (8)
   5. Greet and embrace, flaunting partnership (6)
   6. I meet at approximately eleven perhaps (7)
   7,17. 7 across waters mountain with restraint around the South, but not the North (6 6)
  11. Adaptation from forgotten time in roos Vincent shot (10)
  14. Strict 11 around South East divides Three Ways (8)
  16. Playing a blues ... E coming in handy (7)
  17. see 7
  19. Thrasher playing a blues right ... when left out (6)
  21. Plant cover also embraced (6)
  23. Bits are a bit backward (4)