I remember being being so confident in the two timeline theory from OOT. Got all the prequels in the right place and then it was like lol no, third failure timeline.
Well, that did not seem anticipated at all.
Another option is Broughton, a Labour backbencher.
He wasn't summoned because he was extremely ill, and the implications of him dying on route would not have been good. Either way, that's another route. The only problem is yes he will die and yes that will inevitably be blamed on Callaghan...
I think it was simply too late at this point, the schism was simply too deep between the parties unless either something happens prior that lessens that schism or the Conservative Party evolves in a way that really pushes the National Liberals.