"Bhd seems to have a rule whereby FR are not to compete on any routes already served by another carrier"
I suspect this will not be the case for much longer. Flybe do not seem to be interested in BHD any longer. Routes like NQY although summer only have been withdrawn together with the short lived IOM and frequencies on other routes have been reduced considerably. Also the number of based units is reducing.
I do hope FR start LBA, at least the fares will be more competitive than Flybe and flights are more likely to be on time. Remember Flybe operated LPL from BHD for a time and couldn't make it work yet FR have made a success of it and are adding an extra rotation for the winter schedule.