If the EU breaks up, no one would be more relieved than a Brexiter. It would not be there for the UK to go back to----problem solved!
As it is, UK is, still, sitting on the fence. It does not know, even after three months, what kind of exit it wants. It must believe that EU will be around long enough for them to be able to negotiate something, which wold be a relief for Europeans except that the last thing on their minds is what it happening regarding Brexit.
One shop tried to charge me more money for a stamp, the other day. He said that the UK had left months ago, but I had to insist on a stamp based on EU internal rates.