New Zealand is a smaller country, yes, we know that.
The number of imported cases will scale with the number of passengers passing through the country.
Since the number of imported cases must be an integer, and we are in the position where only a very few cases are actually imported, it is entirely possible for New Zealand to escape infection early in the epidemic because the number of imported cases happens to be zero or extremely low!
By the time we knew what was happening it is likely that significant numbers of cases were already visible in the population.
The excess deaths figure starts climbing (becoming less strongly negative) before the case numbers started taking off - people weren't looking specifically for coronavirus at that time.
So it has a similar economy to the UK, and a similarly urbanised population, but what worked there couldn't work in the UK. Aye, right.
Services are not some homogenous sector!
There are different types of service economy.
NZ has far less international travel per person in the population
New Zealand has a population of 4.87 million, and had approximately
7 million total visitor and resident arrivals in 2019, about evenly split between residents and visitors. That is about 1.4 per capita per year.
In the UK population of 66 million, about
125 million in 2016, which is about 1.9 per capita per year - substantially greater.
We must also consider that this does not include people who do not cross the border and remain airside at transit airports, that can still infect people before they reboard flights and leave, so the true figure will be still higher but I don't have it easily accessible.
Since diseases are exponential in nature, the number of imported cases is less important than the number of people being imported.
Once you get more than a tiny handful of cases it will run away and beyond that the number of cases imported is unimportant. Once community transmission is running away, importing a number of cases from abroad is unimportant because it will inevitably be swamped by domestically produced cases.
Interestingly this is the same phenemona that means that moderated nuclear weapons don't work very well.
The UK was
at least 18 times more likely to import a certain number of cases than New Zealand, and thus would reach the community transmission certain threshold much faster.
The UK likely reached this factor about the time that China finally admitted they had a serious problem in Wuhan.