So has nothing to do with this tincture of moose feet then?
Oh, hell no.
In Australia, POM is, for the UK, much the same as YANK is for the USA. There may have been some derogatory elements in their earlier evolution - and many of us realise they are a term that is applied beyond their original demographic - but these days they are both just a simple descriptive term. Any derogatory component now comes from adjectival qualification.
... so I guess he's picked up a little of our Kiwi twang.
That twang is quite persistent. I was at a garage sale a few years ago and heard a lady there say something. I turned to address her stating "You're a kiwi." She looked at me somewhat startled and told me she left New Zealand 17 years ago. She obviously thought that would be long enough to lose that accent.
I don't think it ever goes away.