The room is large, with a high ceiling. The bathroom is indeed private to the bedroom -its all yours. There is a kitchen too. The host lives in the other part of the apartment, and is very friendly. In fact, if you shut the corridor door, you can enclose the bedroom and bathroom in it's own self-contained mini-apartment, if that's what you want.
There is Wifi. No TV. Reasonably quiet - the bedroom window faces the street, but the street is very residential and quiet, and not on a main car route. It's a five minute walk to Finchley Road tube. Overall: just what I was looking for.