I have a bit of a weird opinion on this. I was very anti brexit. I make multiple trips to Europe every year, probably 4-5 at least. I benefit nothing from leaving the union. My passport is filling with stamps at an alarming rate.
But, to rejoin now after it is done. To rejoin with the basic requirements of a new state rejoining? I don't think it's as great an idea of remaining when we had the perks of an early joining larger state. Certainly you'll find a lot more resistance to replacing the pound with the Euro (I actually could care less, but I'm in the minority here) than there was to leaving on the original terms.
Also, I don't think Europe should have to put up with us (as a whole, the country I mean) whiners. Our bed has been made by the stupidly defined referendum, and the subsequent disastrous implementation and now, we should just suck it up and lie in it.