Update, have looked through everything and all seems ok. No weird wires or pins, things that look too worn compared to when I got the car. Tried to wiggle the plugs there again with the engine on and it acts normal and stays running. 100% start success since the incidents.
Here is a photo of the area, am I missing something that is out of the ordinary as a whole?
The next step will probably be to take it to an auto electrician that deals with older cars. I would consider leaving it with the understanding that the car can be temperamental and like the recovery guy put it ‘maybe just didn’t want to go out today’, but I can’t really risk it bailing on me in the middle of traffic or a worse place like that again, especially if it’s not something that I can pop the bonnet and tweak.
Such a shame for these things, when the car runs it’s a gem, but when it doesn’t.. It picks the worst times.