I recently stayed in the Pumphouse whilst seeing family and friends Christchurch.
The pumphouse is lovely. It was just me staying, but it is certainly big enough for a family or group of friends.
There is a nice we deck area just off the side, which would be a beautiful spot to sit in the morning having breakfast and a cup of tea or at night having a few wines and cheese and crackers (in the warmer weather).
The queen bed was very comfortable and it was a welcome surprise to find a heated blanket on the bed.
Helen was very welcoming when I met her after coming back from a day of visiting.
I would definitely recommend staying at the Pumphouse if you are looking at accommodation in Christchurch that is super close to the airport.