Thanks Mike, although the staff wanted to see my Gold Card record card, after explaining that TfL still haven’t sent it out, I managed to get the discount added to my Oyster (at least I think he did it- but I didn’t have to enter any password or anything like last year, which worries me a bit).
In order to travel on National Rail, which I’ll be doing soon, I still need to chase TfL for my record card though :-/