New Zealand would be interesting but I think by 1815, given Britain being in Australia/New South Wales, they will need to be considered.
That being said, if something can be sorted you could have all sorts of fun with New Zealand and the Maori.
Remember, New Zealand is two large islands, of about 110-150,000 square km size, arranged in a narrow fashion. So the northern part of the North Island is considered sub tropical and the southern part of the South Island is more like the South of England, climatewise.
Now, for Maori, this has implications, as their crop package, so far as they could adapt it to NZ in the 700 (or so, this figure is still a bit uncertain), works best in the Upper North Island, then progressively worsens till about mid-way through the South Island at which point it is very hard work. Which meant that their population was principally in the North Island and northern tip of the South Island (Nelson Bays). In the rest of the South Island they had settlements on the coast near river mouths or fertile fisheries, usually small in size.
So in essence this means most of the South Island is reasonably open to substantial settlement by the Dutch, if they so want to do so. Whether they want to do so is of course the rub.
Large parts of the North Island also proved open to coastal settlement. Many of the NI harbour towns and cities of modern day NZ are based on pre Treaty of Waitangi settlements