I find it hard to think of any mechanism by which the Conservatives could come close to victory in 1945.
Well, to be fair I think Mustard does have that sorted. If Atlee had been stupid enough to compare Churchill and the Conservatives to the Nazis then he would have lost a great deal of support.
That said I doubt he would have been stupid enough to do so.
ITTL, given the set-up, my analysis would be that Britain is heading rapidly for the toilet. It will try to hold on to too much for too long at too great an expense, will fail to provide a safety net worth speaking of, and there will be a repeat of the 20s, only with a less biddable electorate.
I'm not sure, if Churchill actually put forth maximum effort into what was stipulated in the Beveridge report than it would on the health-care front end fairly well.
However, as a leader he had the bad habit of micro-managment which could make everything so much worse.
Empire wise... I can think of only one way that it ends even marginally well for Britain. That is if someone has gotten it into Churchills head that a move towards a united Commonwealth would be more appropriate in the post-war world. Even still, India is going to end badly and large chunks of Africa/Far East are going to be lost in some form or another.
Furthermore, you have to consider what exactly is going to be done with that Empire/Commonwealth. Logically the UK is going to have to sink a massive amount of money (Doesn't have) and manpower into those areas in attempt to development them and make them finanically viable (which basically everywhere in the Empire except India was not.)
Of course, if Britain did somehow manage to maintain a significant part of its Empire and consequently develop it then it would be a superpower but it would be expensive to do and take a bloody long time. Politicians are not known for long-term thinking, most especially the ones that lead the UK through the coldwar.