Farnborough - Warton is actually flown twice a day with a BAe 146 jet. The service is primarily timed to provide a full day at Farnborough for the Warton based staff, as the timings are slightly less optimal for staff going the other way.

The Barrow flights use a much smaller aircraft (a Beech King Air) which typically flies some form of triangular route between Barrow, Farnborough and Filton. Due to the size of this aircraft, the scheduling is slightly more flexible and adjusts to different business needs, whereas the Warton flight operates a fixed daily schedule.

I believe there is also a once weekly schedule between Warton and Munich as well.