Compton3bravo: I'll give it a go!
Monarch Scheduled introduced AGP - ABZ services, with a AGP-based aircraft.
At that time the operating hours at ABZ had been relaxed, so I don't recall this being a factor.
However I think MON shut the AGP base & as soon as they did that, the costs of operating the flights using a MAN-based aircraft rose to the extent that the route eventually became unviable.
I think that's what happened, but happy to be corrected!
Would still welcome MON if they decided to come back...unlikely as that is now!