My stay at Gary's place was pretty much perfect: check in and check out went smoothly, and the host was really helpful in explaining us both the features of the house and how to get around the surrounding. The place is clean, the room perfectly furnished (looked more like a 4-star hotel!) and the bathroom is quite large by London's standards.
The only thing I would point out is the absence of a mechanism to lock the door of the room - of course this is not a concern, considering how discreet Gary is - but it would definitely be a really welcome addition.
In conclusion, I really can't recommend Gary and his place enough, I look forward to visiting London again!