Let's be clear: the City aren't interested in the slightest about who flies the aircraft, or whether there is indeed a "jobs for the boys" culture in the Flight Ops department.
Flight Ops in TCX is the people transport division of the holiday group.
The problem here is there aren't enough customers for holidays, or if there are they aren't paying enough. It's not, per se, an airline problem (who are only reactive to tour ops demands) unless the airline is told to downsize soon.
Putting an extra 100 kg of fuel on won't make a huge difference to the bottom line of TC group, so I would forget any thoughts on that line. The city do NOT understand a flight plan, I can promise you that.
The problem here is that TCG effectively told the City they were headed for Glasgow. Then a few weeks later, they announced all of a sudden that the day trip would end in Carlisle............