Not really. Because it will be tit for tat strategy.

In order to not get job losses, both have to cooperate

You can bet that the big EU countries (Germany and France especially) are going to play hardball to make an example of someone who dares to quit the EU.

Think that would politically difficult at the cost of many of jobs.

Not really. German politicians can just play up the betrayal card - UK leaving means the Germans are now left holding the bag even more for the EU. Germany has a strong economy and this will not affect its fundamentals that much.

Have fun paying import tax on those. Maybe it'll be a good thing for UK car manufacturers. Although I'm struggling to name any.

Have you ever been in a modern German car factory? Nowadays there are huge buildings, spotlessly clean with tons of robots assembling cars.

Occasionally you see someone sitting around reading the newspaper and drinking coffee, ready to jump into action should something go wrong. The times where the industry consisted of huge factories filled with blue collar workers assembling cars by hand is long over.

The industry has two years to focus on other markets to export to. There might be some impact but it won't be catastrophic or lead to massive job loss.