Sebastian's house is absolutely lovely. It is exactly as advertised. (The rooms are very comfy and the beds were great.)
It's in the heart of Stoke Newington, arguably London's nicest neighborhood, and walking distance from Dalston & Shoreditch.
Sebastian was not in London but was a great host, and was available all the time if we encountered any problems. Communication was easy and he was very nice.
I would definitely recommend Sebastian's place for anyone! It's like being in the countryside yet in the heart of one of the most vibrant neighbourhoods in London! Be aware that you need to take the stairs to get to the room.