Long and short of it....we would absolutely stay here again.
We met our host at the flat and he walked us thru the flat and how to work the toilet. Very important....just let go of the toilet chain. I felt like an a$$ when he had to come back to the flat because I thought it was broke. In my limited defense, we arrived very late and I was quite tired.
The flat was fairly spacious and we made use of the kitchen which had everything we needed. The beds were comfy and everyone got a good night sleep until drunks, buses or emergency vehicles came by. If you sleep with the double pane windows closed its pretty quiet. However we slept with the windows open so we'd get awaken every so often. The neighbors in the area are very quiet with only the group of little kids peeking in the window while we cooked once. The flat is solidly built so you dont hear people above or beside you.
The location is great with a 10 minute walk to St Pancras, Kings Cross, and Russell Square. We found ourselves mosytly using Rusell Square as the streets we took to get the station were nearly empty whereas going to KC was a very, very busy road.
For groceries, there is a very small store called COOP very close. Waitrose is close to Russell Square and is a proper large grocery store. There are also plenty of restauranta around to include a little Turkish kebab shop called Cafe Plaka we went to a couple times. If you are in search of Nandos (which my kids were) it is just a couple doors down from Waitrose.
If you are touring the city, this is a great location for using the underground. If you take the Big Bus hop on tours, they have couple stops near by so you can make use of that as well.
If you only take away two things, let go of the toilet chain...dont over think it. And secondly, learn how to get the hot water heater to kick on if you are the 3rd person taking a morning shower. One time was enough for me. ;) just press override on the hot water controller.
ENJOY!