Simply, we were very happy with everything about the flat.
James was helpful in terms of checking in and out times, and giving us his number for any queries throughout our stay. We used to live in the area, so already know that it is a nice place to live, close to central London but not too close. However, the benefit of being right next to a park (with open views from the kitchen) is an incredible bonus which would definitely make us come back. The hill up to it is a bit of a challenge but it's steep rather than long, so is over pretty quickly, and means you get great views.
The flat is well laid out and furnished; smart and elegant but lived in (obviously!) so feels comfortable and easy to relax. Particular favourites were the super king bed and the kitchen/diner - where we could have easily hosted friends.
Searching to find something negative to say, there were a few lights not working and the bathroom is a bit of a squeeze, but nothing significant that affected our stay.