Time for me to pile in too! Haven't taken delivery of my AR yet but I've had the chance to take it for a spin (absolutely loved it) and of course...to check the handbrake. It failed the 'can I push it with the handbrake on?' test. So to my mind it's clear beyond doubt that with this issue being so prevalent amongst such a small production run of cars, this is a design fault. As such, the obligation is on MMC not the dealer to rectify the problem. The dealer acts only as our intermediary.
If any car hits the road with a handbrake that fails the MOT requirements it is not something that any owner needs to consider compromising on or rectifying himself. We all know that we can control cars via the clutch and accelerator and we AR owners now understand that we can increase 'the hold' of the handbrake via the simple expedient of using the footbrake first - but these points are entirely irrelevant. Though some owners may consider themselves competent and ingenious enough to be able to fathom out some kind of solution, it is not their obligation to do so. Indeed I would have thought that there may be some concern here re breaching the terms of the warranty and certainly were there to be an accident due to a faulty handbrake MMC could rightly argue that they were not liable as there had been an intervening act that broke what is known as the chain of causation - meaning that whoever touched the brake last is at fault.
It gets more complicated: Now that we know there's a problem with the handbrake should we even be driving the cars? I know as well as anyone how hard it's going to be to refrain from the temptation of taking the new toy for a whizz round the block but irrespective of how slight a risk one might think we are taking, the fact is that were there to be a handbrake related accident we are at fault for using the car in the knowledge of the pre-existing problem.
Now motoring law/product liability is not my field but as a lawyer I consider myself competent enough to highlight some potential issues here and would conclude with the advice that ARP4 owners need to consider the possible legal pitfalls of driving a car that we know would not pass an MOT test and realise that what we really need to do is not try and fix it ourselves; not try and use the clutch/footplate as a fail safe; not just put up with it as a quirk of this particular type of car, but instead, we should collectively impress upon both dealers and MMC that this is an issue that needs to be resolved pronto. It is their problem not ours. I sense a product recall on the horizon.