Paul,
As you indicate the proof shall be in the pudding, the 'laugh' here is that the tour operator has stated 'we' shall never fill the aircraft for passengers comfort reasons when we, in the know, know that to be downright bullsh1t!
The true reason that it will be ensured the aircrat is never full is because of a payload restriction based on Oxford's runway TODA qand/or the route endurance.
Now if you want to call me a liar then please feel free and go right ahead ...