I stayed 4 nights at Harriet's terrace and found everything to be well above expectations.
The terrace has a lovely layout and the room is perfect. Harriet is a lovely host sharing information about the neighbourhood, restaurants and activities, as well as being up for discussions about books or Brexit or whatever, if we were in the house at the same time. :)
Whether you want the local experience from London, or the full tourist experience I think the location is perfect. I spent time both in the neighbourhood and lazying around at Hampstead Heath, as well as walking to Camden markets and catching the tube to the theatres around Leicester Square and to Notting Hill for sightseeing.
I hope to stay at Harriet's place upon my next visit to London and can only give her my warmest recommendations.