You don't specify if metal and marketing is the same, though. Marketing is what counts so you can fly AY code, BA op as much as you want.
I'd stick to BAEC even when flying to HEL. LHR-HEL is a sort of sweet spot in the system earning 10-40TP (more realistically 10 or 20) in Y and 80TP in J, whether you're on AY or BA code. The watering down of BA operated flights will make it far more difficult to POAG or AUP, though. If you have status with BA, you will get extra Avios, e.g. BA Silver gets 50% extra Avios.
Last edited by remymartin; Mar 12, 2019 at 11:50 am