We had a good stay at Simon's place.
The location is great, really close to the tube and a bus stop, there's also a supermarket nearby and it's also really close to Mercato Metropolitano.
The room has enough space for 2 people if you don't have lots of luggage, the bed is quite comfortable (the pillows maybe are a bit thin). The main problem for me was that the window lets in quite a lot of sunlight, so I'd wake up as soon as daylight came. So if that's something that could bother you, maybe bring a sleep mask.
We never used the kitchen but it looked equipped with everything you need.
The bathroom is tiny but functional and you're provided with a towel each, hair dryer, shampoo and body wash.
We'd definitely consider coming back here next time we visit London.