Julia and her husband Richard were wonderful hosts: thoughtful, tactful and gracious, striking a great balance between anticipating our needs and respecting our privacy.
The space is as lovely as it looks in the photographs, and the view of the garden from the large window is spectacular. We slept soundly -- no traffic noise or noise from the house or neighbors -- but rain and wind did produce noticeable sound effects on the roof and skylights!
The location was just right for our needs (visiting a family member in Hendon, whose flat was not large enough to accommodate us overnight), but as other commenters have noted, you do have to be willing and able to walk ten minutes uphill to get to the bus or Tube in order to reach the usual tourist destinations in London.