Interesting debate. Current wikipedia version of events;
"The earliest references to the beverage date to Australia in the mid-1980s. The first documented appearance of the flat white is at Moors Espresso Bar in Sydney, where Alan Preston added the beverage to his permanent menu in 1985. Preston subsequently opened six more flat white outlets around Sydney's Chinatown area and this is most likely where the flat white gets its Sydney start.[7][8] Alan Preston's seven flat white outlets around Sydney, starting in 1985, constitute the basis for the flat white's rapid take up.[9] Melbourne's claim to substantial influence on the Australian coffee industry follows significant immigration of Italians following the Second World War,[10] and the introduction of espresso coffee machines in the 1950s.
The Wellington claim tells the story of the flat white being invented as a result of a similar "failed cappuccino" at Cafe Bodega on Willis St in 1989.[11] The Auckland claim is attributed variously to Derek Townsend and Darrell Ahlers of Cafe DKD, developed in the "late summer" of 1989 as an alternative to the Italian latte.[3][12]"
Yeah, that's what I heard too. But Miller came to Auckland from Wellington and I seem to recall that he'd already learned to make flat whites there, and he showed the DKD guys how to do them.