> Brexit risks the whole thing collapsing

I know it's off topic, but could you clarify how you could see this happening?

I mean the only issue I can see is that the EU will end up with multiple, smaller finanical centres, hindering scale. But other than that, I can't see the problems of EU with respect to Brexit.

Now, the euro without transfers, that's a bloody problem, but that's been a real problem for 20 years, and no amount of ECB bandaging will fix it.