Kristina's place is an absolutely wonderful stay! My grandma and I stayed, and we felt welcomed and comfortable in her home. The bed was great.
Kristina even watched out for my grandma since I couldn't be there at check-in. She was flexible and helpful.
Also her place is central to most tourist sites and close access to the Victoria line, which will get you just about anywhere, especially regarding transfers to other underground lines.
All in all, if you are coming to London, I definitely recommend staying with Kristina!