Two of us are booked onto BA2563 on Friday (Dalaman-LHR) and I wondered if anyone could advise on upgrading to CE? (I have looked through the site but not had much luck!).

What is the best option for upgrade, given it was booked through BAH? Can we pay to upgrade at the airport, or is using Avios to upgrade before getting to the airport possible?

Any guidance gratefully received!