I certainly think PR is a much better system than the current, in almost any iteration.
But I have to question whether it would have the massive effect on policy some seem to imagine (if I’m not mistaken).
Voting split by party has been really quite consistent over multiple elections, the swing from Con to Labour governments, seems, to mainly revolve around swing voters, centrists, moving one way or the other. They don’t actually vote centrist, otherwise the Libs would pull a bigger share. Now, probably under PR, they would. However, I can’t imagine that parliament under PR would look drastically different from the typical voting split. Maybe many customary Labour voter would go Green, Cons and Labour would lose some to the Libs, more would drift off to extreme R&L parties etc etc.
I don’t see it creating a parliament that will be able/want to push through anything more radical than current system, maybe even less so than where Cons or Lab have an overwhelming majority.