Well done for plugging away at this Steve!
However, like you, I'm not optimistic. We know Northern Trains, like other rail operators, are short staffed, and no doubt they are having to plan their rosters and timetables around that, rather than around patterns of passenger demand.
And I fear the request for 'extra carriages' is unlikely to achieve anything, because the Class 195 trains which we now have on this line are diesel multiple units, in fixed two or three car formations. So you can't just add 'extra carriages' - you have to add an entire two or three-car DMU, and it's highly unlikely that they just happen to have a few spares lying around.
But at least we've now got decent trains at last. It was a long wait.........