The stay at Shimona's flat was very comfortable and felt like home. She wasn't there so a friend of hers let us in and showed the place. Everything went fine and we had a nice stay. To the next metro station it's a few minutes to walk but that's fine and you are in the city fast.
The only little annoying thing was that the key wouldn't turn very well in the lock.
I can only recommend Shimona's place for a stay in London!