We had a great time in Fridtjof's apartment. It is spacious and well equipped with a lovely balcony. We didn't meet Fridtjof as he was away, but he arranged for us to get the keys so it wasn't a problem. Fridtjof is an organized and helpful host.
The flat is well located, it is easy to get around Oslo from there with the metro stop very close by. We would definitely come back and recommend to stay there!