Hi Gizze,
Not good reading I grant you and the delays noted are totally unacceptable. But, again I'd just say that you buy from a dealer not M. It is for the dealer to sort you out a new replacement pair if you get a faulty DSP from the beginning. I know I wouldn't have settled for less. Consumer law says it's you and the dealer contractually IIUC.
I had exactly the same issue with my 1st 861. My dealer didn't hesitate in getting me a completely new unit. Not saying that M are off the hook at all and I do agree it is less than satisfactory but we need to be clear where some of the responsibility lies here.
Would be interested to hear what our resident dealers have to say on this.
cheers