Jon’s attempt at a cryptic crossword

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Across
  1. 2. - A beautiful physician (5,5)
  2. 3. - Carbon monoxide preceding short video (5)
  3. 4. - HIJKLMNO (5)
  4. 7. - A flipped talent show, target of pronounced river rocks banned (6, 2)
  5. 8. - Edinburgh to London booster (11)
  6. 10. - Coat, blade or computer? Jumbled positive ions in anaesthetic emergency (9)
  7. 12. - Hypokalaemic path (4)
  8. 13. - Dracula’s drink with American fuel (5,3)
  9. 14. - Begging of garden with love (5)
  10. 17. - Dwayne Johnson’s favourite neuromuscular blocker (10)
  11. 18. - Seeing tombstones? Sounds like Motörhead lead singer (5)
  12. 19. - Emergency list, mixed up done with Centre Parcs (5)
  13. 20. - Poiseuille’s power (6)
  14. 21. - Buzzing neatly with nitrogen fluoride (8)
Down
  1. 1. - Felling numb, outdoor swimming joins one in walking aid (9)
  2. 3. - Red stripe on the map, blue wave on the monitor (7, 4)
  3. 5. - Diet version of thawed blood product (10)
  4. 6. - regional approach, turn followed by end of canal (6)
  5. 9. - Casual correct dose of any drug (2, 6)
  6. 11. - Looking blue, Grecian low Roman 109 (7)
  7. 15. - Singular McDonald’s burger has lost it’s size, 50% won’t respond (3,3)
  8. 16. - Strength above region (8)