Id say any operator of small jets into LGW is ripe to be taken thanks to the charges. Flybe have cut and run (Dash-8 and E jets), air Moldova (E jets) and Atlantic Airlines (Avro jet) have moved, so, is there anyone else?
Aurigny currently uses AT7s on 6x daily flights between LGW and GCI. As of 31 March 2014 they will use an E95 (leased until June) on five of the six and an AT7 on the other. Fees will still be exorbitant despite the equipment upgrade.
But they treasure their Gatwick route more than anything - though perhaps in a few years there might be a refocussing of London services to provide each airport with 3x daily, thus spreading the cost?