We stayed at Christine's place for a week and found it to be very clean, comfortable and modern. There was plenty of room for the 2 of us but the space warmed up nicely with the heat pumps. It was especially nice to have use of the washing machine & dryer. Christine also provided some milk and spreads for our arrival, which was a nice touch.
Although a little bit out of central Dunedin, the Mornington area will cover your basic needs with a Countdown, fuel station and (most importantly!) a pub all within a couple of minutes' walk. We had our car with us so there were no problems exploring in and around Dunedin, and the on-street parking was right outside, safe and plentiful. If you don't have your own transport you can still make it work; it'd be about a 30 minute walk into the centre or there were plenty of busses passing nearby.
Being very pedantic, the only small issue was that there wasn't enough of some supplies to cover our 7-night stay (coffee, dishwashing liquid, toilet paper). However, that's a minor point and wouldn't impact our decision to book. All in all it's a great place to stay and we'd certainly recommend it!