Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
OK...I solved the problem...the person using the computer...me, in Spain...must be the "processor" of the card. So, being in Spain I could neither have the UK card processed automatically in UK...nor could I manually enter UK card/s on my computer in Spain...as the "UK" field on the "enter your address details"...remained permanently blanked out.
I put my VPN to London...so I became a UK computer processing a UK card...and Bob's your uncle!