Clearly I have the schedule wrong but I thought it was a daily return flight with a second flight on Mondays and Fridays.
31 days in March so that is 31 flights plus another 5 for the 5 Mondays in March and another 4 for the 4 Fridays in March. Total flights 31+5+4 = 40 x 2 for the return leg = 80 flights.
828/80=10.35 passengers per flight.
There are no flights to Berne from Luton.