Baggage Transfer: Flying AY on BE metal connecting with BA flight

[orangehenry]

I'm booking at ticket for my old man flying from STO (either BMA or ARN) to CPH. The only direct flights on a OW carrier are with an AY flight number but flying BE (Flybe) metal. He is connecting with a BA flight to LHR.

As BE are not a OW carrier will they still be able to transfer his luggage through to the BA flight?

Cheers!