As an update: I went back to the retailer where I bought the Q90R to explain the issues I am having with the subwoofer and rears not maintaining connection. At first the guy who sold me the unit was dismissive and kept saying “user error” and “no way Samsung would sell a bodgy product”. So firstly, ********. And secondly, ignorant. Anyways, after telling him I would like to speak to his manager he called his Samsung contact and put him on speaker so I could explain the situation. The guy, Dave, said to just swap it out for a new unit and admitted they have had problems with this batch. He mentioned there is a software update available and sure enough I found it on the Samsung website. I will return my unit for a new one tomorrow and see if it fixes the problem. If not, then I will try installing the updated software/firmware.