I cannot find the details of the Stagecoach fares between Newcastle and Hexham for comparison, but I believe that they are different to those charged by Arriva (I've heard mutterings from those passengers who have to pay) and tickets are not transferable between Arriva and Stagecoach.

Arriva tickets are definitely not negotiable on GNE services (and likewise).

Stagecoach have always required passengers with free passes to state their destination whereas Arriva (and GNE) 'ticket through to the end of the route'.

Stagecoach have for some considerable time now split the route into sections (though with through-ticketing and no change of vehicle) and operate without tachographs, something that Arriva have just recently started to adopt.

Passenger unrest seems to be centred on Haydon Bridge (which also gets an infrequent service from Northern Rail) as well as residents of Gilsland who have now been disenfranchised I believe.