Geoff always answered very quickly to my emails and the organization of check-in has been very easy, with Geoff's assistant coming to welcome us.
The location is perfect (5-10 minutes walk from St-Pancras international train station and as far from Angel underground station). The building isn't very nice, but the surroundings are pleasant, with a square, a street with a market, pubs, etc.
The flat is good-sized, orderly and full of light, with a nice view over the City.
Unfortunately and despite our host efforts, we found it dirty. Good news is: this point can be improved, so that future stays might be perfect!