I would go with the former. Reading that book you sent me in 2011 gave me an idea of the difference between a Kiwi accent and the Ozzie accent when the main character and his friend were joking about how the Kiwi woman said some phrase but being there really illustrated the differences for me between Pom, Kiwi and Aussie.
The Brits and Kiwis really do talk and act more alike (at least the Brits I was around in London and Canterbury) except I heard a couple of Kiwis saying things like 5 dollars
and 55 using an emphasis on
and that I don't recall hearing from Poms or Aussies.
One other difference I noted was that Aussies seem to be more willing to jump into conversation with strangers while Poms and Kiwis were polite but more reserved.
Of course I have been told that us Yank West Coasters and North Easterners are like that (reserved) compared to mid Westerners and Southerners too.
And this is all based on very limited interactions.