Not long until significant economic convergence, what's your predicted time frame ?
I think we will be back in the Single Market in the next but one Parliament.
I believe Labour will win the next election but inherit a huge economic set of problems (in part driven by being outside the SM). They will not campaign with re-entering the SM as part of their formal manifesto and won't get it done in a first term.
I think the Conservatives will marginalise the ERG for the next but one election, or will self combust and divide. Either way I think a SM dimension will be included in the manifestos of that particular election.
I think the EU would welcome the move and accelerate things too.
As a Leave voter, that would please me and feel like what I voted for.
Who knows, nobody has a crystal ball.