I am persuaded by the figures to think that the conclusion is plausible. A pity that a bit more of the method has not been explained to the nay-sayers, but perhaps it would not make any difference to their closed minds. They would also need some training in Bayesian statistics.
Bayesian Theory. Further analysis could be done, for example with the full list of sales.

The whole point of the Bayesian analysis is that we do not know where the buyers are from because they were not asked and it is not recorded in the sale documents. The government defence is that it is not a problem because we don’t know.
But we (and the govt!) can do some Bayesian analysis with other things that we do know (eg surnames) to make an estimate. This can be combined with other information to refine it, such as name frequency, spatial patterns etc, from the census that do have details of ethnic ratios. It is all a pretty standard methodology that has been used for over 100 years.

It is just ignorant by correspondents to say that since they have an asian sounding name yet they are not Chinese the whole analysis is invalid. The individual is statistically insignificant. The fact that there are a certain number of citizens and residents with non-european names (5%) was properly accounted for in the analysis.
Likewise the claim that the numbers for Indians are all students is plain silly. But I suppose that people do not read following comments. The Herald article hinted at the data sources used and the methods, but probably was not appropriate to put more in a newspaper article. But since I can do this sort of maths I get it.

There are other legal, open, sources of every sale in NZ. This could have been used with the ‘leaked’ data. Perhaps it was. The electoral roll is great for a list of surnames . The sales data and ownership is public information on the web that you can get but it costs a lot of money. Anyone can get it for each property on the internet by paying for it. But even if we actually had all the details of the domicile of every sale would the government take any action. It seems to me that for various reasons that they are not willing to articulate that they encourage the investment especially to balance the terms of trade figures.