We visited Christchurch during the day and had booked Sumner based on reviews. We were not disappointed, 15 minutes drive out of town to the very nice resort of Sumner. The retreat has been built by the owners with 3 apartments, 1 studio and the owners own apartment, all accessed by lift. Added to this is a small pool and hot tub and a lovely roof top area with great views. The studio is ideal for a couple and we would have happily stayed longer than the one night we had booked.
Around the corner were at least 5 different restaurants- we enjoyed a meal at The Village Inn.
Overall a great place to stay.