Yep, looks like they're getting ready to leave.
As a City observer said yesterday, "Good luck, and enjoy your holiday; because you'll be back."
I suspect that even if Brexit was reversed (by Parliament throwing out 'the deal' - when we know what 'the deal' is, or no deal), a second referendum, a change of PM, or another election, the damage to UK economy is already substantial and probably irreversible for many years.
Depending on the disarray or the timing of the 'change of heart', the economic damage might be permanently irreversible.
If sufficient financial institutes move out of London, and a new successful financial 'city' is established in Europe, there would be no sense in those institutes moving back to London if Brexit was reversed.
In my experience many, many under 40's Europeans speak good English, the majority of under 30's speak excellent English, and English (or another European language) is taught in most western European primary schools.There is also the language. I can see lots of worldwide banks, like US, Singapore, Chinese etc will prefer to operate from an English speaking city, since for most of these that will be their 2nd language.
Why is David Davis refusing to release them?