I had a really good time at Marias Airbnb. She was very helpful with questions on train services to the airport and the London underground system (Oyster card etc.).
The room is big enough and equipped with nice details and because her house is on a side street there are no traffic noises so I could sleep very well. I am especially thankful that she offered allergy free (lactose intolerance) breakfast! That was awesome :)
Marias house is close to the subway to the city centre and to bus or train connections to Stansted airport. All in all, I really reccomend this accomodation. You should stay here if you want to have a nice time while being in London.