We had a fine stay at John's place, which is very well described as cosy. Not huge, but spacious enough for a couple, especially with the nice high ceilings. It is quite tastefully furnished, with John's lovely collection of art and design books an added bonus!
The sofa turned out to be exactly the right size for our 6 year old, so that worked out perfectly for us. All the fixtures and equipment worked fine, and were able to cook, etc quite easily.
The location is good, on a quiet street but only a few minutes away from a lot of shops near the Tube station.
The exterior of the building is fairly shabby though, and the staircase a bit dim (it's a one floor walkup), so we were somewhat worried as we came in, and it was a relief to find the interior to be a clean, well-lighted place, with even a garden view. Of course one doesn't see the outside when sitting inside looking out!
John was quick to reply to email, and generally easy to deal with, although we had an honest miscommunication about the arrival time that left us briefly worried at the front stoop.
In short, I would recommend this place.