Surely it's not the load factor which is important, it's the total revenue (ticket plus ancillary) from the flight. There's no point in filling the plane if everyone is paying loss leading fares.
I notice from EDI at the moment most flights are showing ca £150, which expect is below cost, but in the peak season this summer they're over £300, which I hope isn't.
Certainly they should slow their route growth, and seek to lease out some planes,say to the growth markets in Asia.