My wife would like to book a ticket and upgrade it to WT+ using miles from our household account.

Her (Gold) membership is registered in Spain, but the CC we'd like to use is UK registered.

Is there a straightforward way to do this?

She tried calling BAEC UK who directed her towards the Madrid office instead. The staff there were rather unhelpful and said that she'd have to book the revenue ticket first and then call another number to request the upgrade.

Is there something especially awkward that means Madrid can't handle a booking & upgrade in one transaction?

I wondered if we could book the ticket in a BA travel shop and pay on the spot (avoiding any Cardholder not present issues), but according to BAEC this is a no go.

Any and all advice most welcome.