I'd recommend Barbara's place if you are travelling alone and would like to stay in a quiet area with good connection to the city center. The apartment is located 5min from Preston Road station - Metropolitan line, so it's easy to reach any part of the city. Stop for buses serving the Wembley area is in 1min.
It was easy to find the place and get in as Barbara gave detailed and clear instructions and was also very quick and kind in answering anytime I contacted her.
The apartment was clean and equipped as in the description.