I think you're massively underestimating the appetite the population has for an actual left-wing government. The conservatives lost power because of how awful they were, they have demonstrated that they haven't changed and reform are even worse than they are. It was a mistake for reform to gain council seats they've now just demonstrated their incompetence quite publicly.

So what we're left with is a bunch of proven uselessnesses, a sleepy lib dem party that's unlikely to wake up anytime soon, vs whatever the flaming hell Corbin ends up calling his party.