Even if that's true (and it probably is, because it was a pretty thin majority to exit in the first place) it would be absolute political suicide to go into this election on the promise of getting us back in.
The anti EU brigade are lunatics and people who voted leave are easily lead. The last thing we need is "Look, they're ignoring your will!" followed by Emperor Farage...
It's a completely moot point for another reason. The EU isn't just going to let them back in with the same sweetheart deal they got as founding members. That alone means this won't happen for decades if at all .
That will never fly with the public , especially since one of the "normal" conditions is giving up the pound, joining the Euro, and giving up direct control of their monetary policy. There is no way a majority would support that in the UK . None of these polls will even bother asking something like that. The polls are about whether they want to turn back time to before Brexit, which is somewhat interesting but isn't possible.
EEA does allow free movement of people though, which is most of what made us leave to start with. Mostly because of this prick pretending that hordes of dirty brown refugees were somehow the fault of that.
Would be kind of funny if the reverse of Brexit happened. Have some pro Europe lunatics take over the fight and make a brexiteer accept the worst deal to re-enter the union.