This place (and Serena) were great! I would highly recommend it! I read through a lot of reviews to plan my trip to London and so I'm hoping to return the favor with a helpful review.
Location: The location is perfect! It's in a safe, clean area and it literally take less than a minute from the flat door to the Tube entrance. This is probably one of the best things ever. I was able to swing by the flat for a quick break without feeling like I was wasting a ton of time. Also, for those who haven't been to London before, using the Tube, you pay by zone (to a certain degree... look it up) and the Tube station makes it even better since you're in the right zone.
Communication: As a new airbnb-er, I had no idea what to expect but Serena would email and text so I never felt confused. She was great, welcomed me, checked in, and I couldn't ask for more.
Accommodations: While I feel like all I need is a bed and shower, this was more than that. Having a room with a door and a nice bed was great. Although I went during November/December I was never too hot or too cold. It was freezing outside but never inside. Serena was around for the last few days I was there but we never had to fight for the bathroom. In fact, I'm not sure if I was ever up or around when she used the bathroom.
Overall: I really can't think of a reason why I wouldn't go back. I know I'll be back in London soon and know that I'll look to see if Serena's place is available first. I highly recommend her and her place!