Christmas cryptic

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Across
  1. 2. Santa's favourite (7)
  2. 4. Incorrect coordinates due to embellishments (11)
  3. 6. Decorated with baubles (9,4)
  4. 7. Treat specimen incorrectly with iodine (9)
  5. 8. Christmas rock star (4)
  6. 10. Monarchs after inventory of chaps (9)
  7. 12. Go insane after trunk of trees (9)
  8. 14. Killer whiskey with Christmassy tones (6,5)
  9. 17. An own-goal score ruined the Christmas spirit (7)
  10. 19. Add three grams to one shaken beverage (6)
  11. 20. Good king who likes his pizza (9)
  12. 22. Celebrity sits arrested oddly (4)
  13. 23. Outcast happily takes the start of Christmas (6)
  14. 25. Gifted rhymer carelessly drops drug (5)
  15. 26. Secrecy agreement with a relevant CD mix is in the build-up (6,8)
  16. 28. Sweet loaf taken illegally? (7)
  17. 29. A mix of leaves drop Autumnally for fairy folk (5)
Down
  1. 1. Apparently, swine testicles are decorative (7)
  2. 3. Clumsily patent a christmas pudding (9)
  3. 5. Christmas dinner where St Nicholas is from (6)
  4. 7. Broadcast announces airstrike on foot of plant (9)
  5. 9. Drunk, wellied model united nations' refreshment option (6,4)
  6. 11. Mary's husband (6)
  7. 13. Snakes mixed up Christmas gifts (7)
  8. 15. To be honest it smells good (12)
  9. 16. The start of lengthy obituary, perhaps, cooked as winter kindling (4,3)
  10. 18. Inside there's no way of precipitation (4)
  11. 21. Ball-breaker (10)
  12. 24. Intense anger about Eastern floral arrangement (6)
  13. 27. Gift at the start of Autumn (4)