I was under impression that whatever you just mentioned would have happened by now, but Nissan and Unilever are now moving to UK and all the speculations are going down the drain.
I have come to a conclusion that all the anti-brexit hysteria has been priced in, and indecisiveness is proving more costly as time goes by!
So, the Unilever thing is a stock move, that really only occurred because the shareholders in the City didn't like it (being removed from the FTSE would have been very bad for their share price).
My understanding is that Nissan (and all the car-makers) rely on frictionless trade in goods, which probably isn't going to happen. I believe that they will probably invest in the UK for the domestic market, but we'll see.
Again, nothing has practically changed in terms of trade, and will not until January 1st of next year. We'll see I suppose.
As an outsider, for something as zero-sum as buying a home where supply is low, cost of waiting and indecision can be pretty high.
Firstly, Brexit has still not happened in any real sense (there's a transition period till the end of the year).
Secondly, the UK government appear to want a minimal trade relationship with the EU, which will hit services trade pretty hard (and the UK exports lots of services).
The likelihood is that many large companies will need to move staff/assets to the EU to retain their licenses.
For me, specifically (as I'm a data scientist) this probably means that data products out of the UK are going to be tricky to sell.
I would expect that there will be a drop in London property prices, but a larger drop in jobs.
Don't get me wrong, London is a great city, but I (personally) would stay away from moving there till at least next year, as the implications around Brexit and trade should be much clearer by then.