I still think that so-called advice that Mason regularly and tediously gives out about pointing some Windows 3.1, cheap and nasty dash cam to the side window to film an irate driver threatening you is completely irresponsible. If you must risk getting your head further kicked in by doing that, then you would get much better quality and more accessible footage by pointing your mobile phone at them and filming them that way.
The last thing I would do in that situation would be to start pointing a toy camera at somebody, in such a state of agitation, that it would be quite possible that they could decide to smash your window as a result, and then get into the car to get hold of you. What I would be doing, rather than fiddling with a Matchbox Superfast ‘Drive Like Dad’ dash cam, would be phoning the Police and making the person aware that I was doing that. Equally, that could still inflame the situation, but at least they would know you were being directly proactive, rather than waving a rubber representation of a dash cam from the last century out of a Christmas cracker at them.