A good illustration of the difference it makes whether one four/five car set turns up or two on the Voyager routes: I travelled from Chesterfield to Leeds on the 0905 Edinburgh bound service yesterday, and I only attempted it because it was allocated as 4+4 coaches (2x220) - and even so, nearly every seat in both sets appeared to be occupied, including most of the rear 1st class, despite it having no catering. So it's quite clear why such services get to be so hellish when they turn up as one 4 car set (and I've seen this particular service get allocated as such). Two full train loads in one set.
Meanwhile, mass cancellations again today on the Nottingham->Birmingham->Cardiff route, including three in a row at one point this afternoon.
This franchise should be one of the first to be fully nationalised, not because that would immediately fix the problems (obviously it won't do so in the very short term) but because at least we wouldn't be paying a private company commission/fees/however it works currently for the privilege of having a lousy service.