Well on 20.6 the flight was scheduled and was operated by G-GDFD which did not fly earlier on that day.
It is certainly the case that the crew might have operated another aircraft on that day but departure being scheduled at 08:30 I don’t see any “eligible” inbound Jet2 before 07:30 (although I don’t know Jet2 specifics I’d wager that they have to report at the aircraft at least 1h before departure). So my take is that it was the first flight of the day for said crew. How did they “unexpectedly” get out of flying hours ?