> I feel the UK were wrong to leave [..]
Whether it was the correct decision or not, it was done via a democratic vote. Now the leaders of the UK look to entangle the UK into the EU structure that is evidently against their mandate.
The vote was to leave or stay - there was no mandate for or against a specific relationship to the EU before even considering how drastically opinions have shifted since.
That mandate has quite changed, even more when you look at the non-retired cohorts. Reintegration with the EU will take plenty of time.
The vote wasn’t binding and had a low turnout. Not really a good example to point to for democratic voting
The majority of UK inhabitans wants to rejoin the EU. It is indeed democratically legitime.
Democratic vote which has since then been proved to be heavily influenced by the Cambridge Analytica campaign, so which probably did not reflect the actual opinion of the population. It was a manipulated vote.
The current UK government was also elected by democratic vote, so they have a mandate that postdates the referendum.
You can argue their mandate is invalid due to the first-past-the-post system, but in that case the original decision to hold a referendum, and all subsequent governments that negotiated the terms of the EU exit are also invalid, since they all derived from first-past-the-post elections.