This is a lovely attic room in a peaceful, green neighbourhood. I stayed with my two sons (12 and 15 years old) and the room was perfect for us. Nice views over the city from the windows! If you have bad knees, plenty of luggage or small children, the other room in the house might be better as the spiral staircase is pretty steep, but for us this was great. Very cozy! Sharing the kitchen and bathroom with the hosts was absolutely no problem, the hosts are friendly, nice and helpful. The only thing is if there are guests in the other room too, you might have to wait for the bathroom/shower in the morning. But as long as you are aware of that, it's not a problem.
The system with the key box was very convenient!
There is also a very nice park with a playground just across the road. The station "Queen's park" is just a five minute walk away, which makes it convenient to get into London, or further out to Watford Junction in case you're going to Warner bros studios. :) I am very glad I chose this for our stay in London!