This kind of polling is pointless.
Brittish media/government never really mentioned the concept of "ever closer union". To the average British citizen the EU was primarily a trading block that was to blame for everything wrong.
You can see it in things the UK vetoed (e.g. EU Defence Army, Euro, etc..). There was never interest in "ever closer union".
For Britain to rejoin it would need to accept the concept of "ever closer union", but considering half the country was sold on "muh sovereignty" its highly unlikely people would want to give up what the EU would demand.
The ideal would be to scrap the hardest of brexit style deal, for something closer to EEA. Give the UK to figure itself out and move forward with the ability to rebuild ties.
While I think the next election can bring a change in political will from the UK side, I think many in the EU were upset and there isn't the drive to improve relations.