For prosperity I'm noting down an old memory to pin down Flat Whites in Wellington.
In a no longer extant underground cafe, I got sort of made fun of in the 1990s poor customer service manner that existed in Wellington at the time.
I was with friends for what was probably my 20th birthday, certain some birthday, and the counter staff made fun of my party for wanting a both a flat white and a latte, affirming incorrectly that they where the same thing.
That made it 1996, I think, which had Flat White's as an orderable drink at cafes across Wellington.