It's interesting what you stumble across while looking for something completely unrelated. This is the Response - Official Information Request to a query about the toilet block at Hank Edwards Reserve:
The public toilet facility at Hank Edwards Reserve is the only public toilet facility available in a perimeter of approximately 10km. The next available public toilets are in either Otaki or Levin.
The total cost of the project is $369,687 plus GST. This equates to a cost of $354,628 (plus GST) for the ablution/changing block, and $15,059 (plus GST) for the BBQ and tables.
Much of the request (555 KB PDF) is rather silly, but the cost information is useful — although the information was provided long before the building was completed.