[bag02craso]

Going to try this myself, got a serial which is under warranty bought in 2017. Do I just register the serial and contact support and  do what mothered suggested and say they were admitting a loud sound i.e something relating to health and safety.

Good to hear man, can't wait to hear about it. Just start a chat with them, then they will create a case from there. No need to register anywhere.
Regarding the reason/method, you should definetly follow @mothered advice previously in the thread.

Did exactly that, did register then did chat took mothered's advice. Will get a call within 3 days so should go well hopefully. Do Bose replacements arrive just like if you bought it retail? i.e no "Replacement not for resell" marks on it and includes the standard accessories?

Good luck with the SE. Their should not be a mark on it regarding reselling.