I’ve also just upgraded gold to platinum and have a couple of Qs:

(1) I cannot see my membership rewards balance online and when I click on the membership rewards link it’s asking me to register the new card for a £23.50 fee (waived for Platinum members). Do I just need to wait a few days for my old balance to show up? Presumably any purchases I make with my existing gold card until the plat one shows up will earn rewards as normal?

(2) do you get the 5k bonus for adding additional cardholders just for the first supplementary Plat or also for the additional gold cards you can add?

Any recent experiences? Thanks in advance