I don't think the aircraft is BLK based for the initial BFS flight from 4th Nov.
From the Timetable page
LS721 departs BLK at 1440 to BFS and returns to BLK at 1640 as LS722
However if you try to book a flight
LS722 operates BLK to BFS and arrives at BFS at 1640. LS721 is the BFS-BLK leg
These directly contradict each other!
For one flight 4x per week it would be a stretch even for Jet2 to have the aircraft parked at BLK for all except 8 hours per week! Or are they starting a mail contract from BLK?
When the other two flights start there will be one flight on Mon, Tue, Thu and Fri with two flights on Sat & Sun which seem to be done by a single aircraft if I'm reading the Timetable pages correctly.
PTH