Dean is a very nice and friendly guy, who reminded me of Crocodile Dundee somehow : - )
The accommodation itself is actually a rustic hostel in a pub, less so an airbnb- some quite compact dorm rooms and one double room. We booked two dorm beds, but upgraded to the double upon arrival. Indeed the booking, even though we entered "two people", was only valid for a single person, so the double room was not much more expansive, than two single beds. Also, in terms of sandflies and fresh air, I´d advise to opt for the double room, as the dorms are either full of flies (windows open) or you can´t really breath (3-4 people in a really little room, windows closed). As there are no sockets in the dorm room, you also can´t install an electric mosquito coil or charge your phone. Also, the wooden bunk bed was squeaking with every movement, and as the dorm rooms are facing towards the street, truck traffic would be an issue at least for light sleepers.
If the hostel area is busy, which it was during our stay, a little downside are the thin walls- in every room you´d hear every word spoken in the common area, as well as every door that is opened or closed.
The Berlins has a good strategic location between pancake rocks and Golden Bay / Abel Tasman, so one night in the double would be ok.