as the last edition of the guide was published in 2012 I wonder if you already know when the next edition will be published.
The next edition of The Rough Guide to New Zealand is planned for publication in September 2015 at the moment.
I hope this helps!
It’s still scheduled for publication on September 1st this year, and will be available to buy on that date (print and ebook). Amazon is taking preorders now: amazon.co.uk/Rough-Guide-New-Zealand/dp/0241186706/ref=sr_1_2?s=books&ie=UTF8&qid=1439457689&sr=1-2&keywords=rough+guide+new+zealand
Hope this helps!