According to a gov.nz site
"In 1948 New Zealanders became New Zealand citizens – before that they had been British citizens."
So Hillary would have been a British citizen most of his life and possibly acquired a liking for marmalade while in that state.
While we weren't technically independent, we'd been self-governing since 1865, although it took us a lot longer to cut all of the apron strings, and well, the Queen is still our head of state, so who knows if or when we'll go full republic - most NZers don't really care. But hey, in the 2000s we stopped using the Privy Council in England as our highest court.
http://www.firstworldwar.tki.org.nz/assets/Uploads/Images/Y5...