How long until the UK could stomach a vote to try to go back? The tories won't consider that, but if labor comes back into power, would they want to immediately try to reverse that vote, what a mindfield.
This is complicated by the fact that the whole process of re-joining would likely take longer than a single term to complete, and the EU is unlikely to start that process until they believe that support for it in the UK is strong enough that the whole thing won't just be abandoned part way through due to a change of policy or party in government.