Just got to that bit. Italian build quality. The left hand speaker had 3 (yes 3) of the bolts that hold it on totally loose. 2 of the 3 bolts were barely hanging on by one screw thread. The RHS speaker was better but not as tight as they should be. Explains both the rattle over bumps and the rattle whenever I turned up the stereo. The washers between the nuts were bouncing around like symbols. All back together now save the centre arm rest housing which only had 3 of the 4 clips fitted (more exceptional attention to detail). I checked to make sure I didn’t break or drop one but it’s not there so ordering a new set to ensure they are tip top (£7 from eurospares and in stock). I’m pretty sure no one has been in there before me as it’s a 2019 car with low miles.
I’m glad I took on the job as a few more miles and those nuts would have worked their way off altogether and headed off to god knows where to be heard but never seen again. As an aside the quality of the Harmon Kardon speakers and subwoofer was a bit of a shock. Cheap doesn’t begin to describe it.