Recently booked a redemption ticket using CX Asiamiles. Outbound from Hong Kong to London on BA. Inbound from Madrid to Hong Kong on CX. Both business class.

Silver with BA but none with CX. Already add BA FFP to booking. However, when entered PNR on BA app, it shows “Seat choices are only available at check-in.”.

Any chance I can choose a seat in advance for free?

Any recommendations on seat selection on the B773?

Thank you