What I don't understand
Is why you'd do such an important vote by a simple majority. Seems to me that you should require 2/3 majority, so it is clear that the population wants such a major change. What would happen if a few years after Brexit there's some buyer's remorse and a new referendum is called and rejoining the EU gets a 51% majority? You could end up flipping back and forth when you only need to win by one vote either way.