EI-BUD
this has not been uncommon with BA in the case of airlines it has taken over
Don't forget to add Manx Air to that list. They had four pairs per day at LHR and got bought up (for the second time) and rapidly shifted to LGW - and then disposed of (for the second time).
I suppose that's the free market but it's a also the direct result of slot constrained LHR and that is the fault of successive govts - but let's not start on that one again!