Manifesto Snapshots Watch
It doesn't look very neutral!
This might help.
Worth noting that some people may well be voting tactically by voting for smaller parties that would probably never get a majority
I know the information is out there, but (as far as I'm aware) TSR is at least notionally neutral. Only covering the left wing manifestos doesn't really fit with that!
You do raise a good point... TSR, how do you explain that one?