Life doesn't revolve around the Channel Islands.
For a start the Jersey Dash flies onward to the IOM during its duty JER-LCY.
The inter-island Dash comes from Exeter which also goes onto Dublin. Also the Dash Q400 comes inter-island from BHX, it also has a program out of BHX.
The other Dash into JER from LCY comes from BHD. It also has a full program elswhere.
So minesagrolsch, Flybe's aircraft are not all dedicated to JER/GCI.
Flybe have to remember to not P*** many other pax off by fouling up the other parts of the jigsaw puzzle.