Haha oh, it was bank account.
Seems to be an issue with the application process for the Premium account where it's not asking for the Joint Applicant information.
It just goes, Joint Info (tax status etc), Main Applicant Personal Info, Main Applicant Money Info, Credit Check, Submit application. Then annoyingly to switch it to a joint account i was told we both had to go into a branch within 7 days, which i'd rather not do.
If you can help i'll shoot you a PM, otherwise i'll just stick with Natwest