I had a pleasant stay at Riona's place. Hampstead is one of the most beautiful places I have been and the apartment is just a block or a few from some of its most charming neighborhoods. There are 4-5 classic British pubs within a short walk and one next door. (Note that noise from the pub or elsewhere was never an issue -- it's a pretty low key place).
As a host, Riona was always responsive. She helped with some WiFi issues by calling the internet company. Also, she twice Uber'ed keys to me when I locked myself out.
As for the apartment: ideal for a short visit, but maybe not a longer stay. The shower is a bit small and because it does not have a full enclosure, water does tend to get on the floor. Also there is no dryer (I had to rig up strings in the bedroom where there is already not a ton of room). The amenities are sparse (e.g. very limited storage space for clothes, no trash can in the bedroom, limited cooking equipment in the kitchen). Nonetheless, Hampstead is worth it!