PURELY SPECULATIVE! But: Cityjet is reducing LCY, so LCY will be keen to attract additional custom. BE has the appropriate planes, do the DASH8/E175 need any steep approach equipment/training? Linked to this: Rumour is that FMO will announce a new London route to start in May, with an airline that has not previously flown regular FMO services...
I find it very hard to believe that Flybe would open up LCY by serving a destination such as FMO....