Finally got round to booking my F56 into the dealer for some investigative work for rear knocking :(
It's pretty much done it since new but I never seemed to get round to doing anything about it! But I've discounted the fake boot floor...it knocks when up and down, taken out the tyre pump etc and it's still the same. Only when we had a big case in the back did it stop, hence why I think it may be the suspension but knocks can be elusive! It does soundthe same as when my RCZ had faulty front suspension mounts.
The car's booked in on Monday for a couple of days so I really hope they find the problem ......and it's covered by warranty!!!