Well the aircraft only sit idle for 24 hours due to LCY shutting at lunchtime saturday and reopening sunday lunchtime so thats not nearly 2 days!
According to the timetable, Cityflyer LCY-ops more or less end on Friday evenings and resume at 5 pm on Sunday. The only exception is a sat morning departure to EDI and two early afternoon departures on sundays to BCN and NCE. So it is closer to two days than 24 hours.