Me and my family stayed for 10 days and we can say this place is really beautiful.
The studio apartment is spacious and clean and the garden is perfect.
The apartment is located in a peaceful area right on the edge of Richmond Park, with a private gate to Sheen Park. It's close to public transport and it's easy to reach the center.
Also, Peter is a friendly host.
I would have given this place a 5 stars if there weren't one particular issue with the heating. We stayed at this apartment on November, when it's pretty cold in London (I'm from Israel, so 10 degrees is freezing for me). The apartment's heating is controlled by a main controller which is located in the main house, and is shut down at night (12:00am-6am). We did NOT know that.
After our first night, which was a particularly cold night, we talked to peter and asked for the heating to be left alone. I'm afraid it didn't work and the heating was shut down each night at various times. One time it only turned on again at 8am (after I messaged Peter the heating is off again).
We already traveled to Europe in the Winter and we never had heating problem.
I think that once you rent a place through AirBnB you want to have full control on your rented space which did not happen in this case.
This is a beautiful place and Peter is very nice, but If you are traveling in the winter perhaps talk with Peter beforehand and clarify your expectations.