5 years on its own is not long enough to effect lasting change. What Labour need is a shift towards them that is likely to last beyond one term.
I hope they've got that (although I am actually a Green supporter at heart), but it doesn't look like they do.
At the moment it looks as though a Con/Ref merger could beat Labour at the next election. And the Con / Ref parties will have spotted that too. This is what I meant about Farage looking for ways to build influence.