Brummy,
As far as the whole 'who paid for their seats and who didn't' question, you need to remember that the people dealing with the aircraft trim and therefore the moving of passengers, are not Flybe, but their ground handling agent. It's very unlikely that the dispatcher dealing with the flight has any access to, or any interest in, the pre-payment information. Their job is simply to get the flight sent out on time with the minimum fuss. The computerised system used for producing the loadsheet, is not necessarily the same system used for checking in passengers, and the passenger handling team and dispatch team have fairly limited contact (at least in my experience).