THE HOLES DO NOT NEED TO BE SEALED.ceilings are compartments rated to 30 minutes so the holes need to be sealed and a 30 min resistance maintained
READ THE ARTICLE AGAIN.
KEEP READING IT UNTIL YOU REALISE THAT IT REPORTS THAT TESTS DONE BY TRADA SHOW THAT DOWNLIGHTER HOLES IN 30 MINUTE CEILINGS DO NOT POSE A PROBLEM.
irelevent in terms of the requirements of 517 though, you could learn something if you were less aggressive