Andy and Mark's flatlet is quite cozy and diabolically clever in design. They're both architects, and have managed to take an unpromising basement space and make it functional, comfortable, and quite elegant. The place is very well outfitted with a sitting/sleeping room, large bath, and well-equipped kitchen [though the one-burner hot plate works against major meal preparation], and the inclusion of large glass doors at the entry and between the bath and kitchen make the space much lighter than one might expect.
The best thing about Andy and Mark's space, it must be said, is the location, just off Newington Green. I'd never been to Stoke Newington before, and the area in which the flatlet is located is beautiful to look at and enjoyable to explore. The green itself, a lovely urban park, is surrounded by first-rate restaurants, and you won't have to venture far to enjoy yourself in that regard. I loved the surroundings and would happily return to them.
Two caveats. Though Mark explained that the ceiling was insulated, the noise from directly above - mostly the pounding of footsteps - was, to this visitor at any rate, quite disruptive. Mark told me that no one else has mentioned it, but I am quite noise-sensitive and found it to be noticeable and unpleasant. The other issue has to do with natural ventilation. Though as noted there are two large sets of glass doors, and when you open both you get a breeze through the flat, there are no windows. Thus at night - unless you want to leave your doors unlocked and ajar - you don't have fresh air. Mark very graciously brought me a giant-size Dyson fan which kept the place cool, and that partially rectified the issue.
Despite these issues, I found the flatlet to be very comfortable, the neighborhood to be beautiful and quite convenient to the Overground train, and the experience to be a most enjoyable one.