No forensic evidence, it's not needed, just ask the experts above, they seem to know more about Flybe's business than Flybe itself. Companies must be queuing up to recruit them on a "name your salary" contract.
You can park the sarcasm unless that's your only means of response.
If you go to flybe's Investor Relations page, you can download the H1 presentation which was released on 9 November. Go to page 8 and you'll see the entry reported "includes LHR" with a negative £4.4m change. There is no other supporting stuff as to how the LHR routes are performing and nor I guess are they required to provide any. However it's fairly clear that they must be making a loss even if running full - which is possible if yields are low but costs are high.
If you do a few Google searches then you'll quickly find some pieces about performance in Scotland. If questioning the economics of running an Embraer 170 around with a single passenger aboard makes me an "armchair CEO" then that's a mantle I'll happily wear.
And if you're a Flybe employee who doesn't see any of this as a challenge or even a big issue, then good luck to you. You'll need it.