Just returned from my visit to London and stay at Whitney & Lukas' flat. Beyond the great location and cosy & comfortable accommodation, Whitney & Lukas were marvelous hosts!
They coordinated all details seamlessly, left me thoughtful suggestions for things to do based on my interests, and periodically checked in to make sure my stay was comfortable.
Highly recommend their flat - its close to the city center and desirable neighborhoods like South Ken and Notting Hill, but also very residential and quiet. Also has great access to 2 metro lines including a direct connection to Heathrow.