If the OP doesn't mind, perhaps I can partially answer that one. Salaries used to be lower than the UK for similar roles but that has definitely changed now due to increased salaries and the pound taking a battering. My wife and I both earn more than we did in the UK.
Auckland is an expensive city particularly for rent/mortgage. Prices for a 3/4 bedroom house are probably between $650k - $1m+ for the nicer parts of town (i.e. not South Auckland). Of course, this will vary by suburb but even the 'just ok' areas are fairly expensive.
Some food and drink is generally more expensive as well. A loaf of bread is $5.50 for instance yet fruit and veg tends to be the same or slightly cheaper (Note : New Zealand is very seasonal so prices fluctuate wildly). I might actually look at some proper stats to see how it compares to the UK. My feeling is that it's probably comparable when buying from the supermarket and slightly cheaper when eating out.
Anyway, don't know if any of that was any use as it's not particularly scientific