Your bets are already wrong. People are literally posting in this thread about them being told to relocate. It has already happened, and will happen - London cannot be the centre for EU financial trading outside of Europe. Frankfurt will absolutely gobble that up, and the EU will ensure that happens.
Companies are *already* planning to move - this isn't a theoretical thing. It's happening.
Dublin is going to make a strong play for them as well.
You remember that scene in Jerry Mcguire? We need someone to do that as a GIF...