Cecilia's studio is very well located, a short walk to the tube stop, several museums, and Hyde Park. It's a good sized space for a London studio, especially if you fold the bed up during the day. The kitchen is small, but functional, and Cecilia even left some tea and cookies out for me. It is at basement/ground level, but since it opens into an enclosed back garden, it's very quiet, safe, and secure. The two big windows make it quite bright, and there's a surprisingly nice view of the garden foliage. Perhaps because of the age of the building some things didn't work perfectly, and a few corners were a little dirty, but overall very comfortable.
Above all, Cecilia is a very invested host, she did a great job communicating with me before and during my stay about any issues, and checking in that things were as expected. When it turned out the fan was broken, she tried her best to replace it as quickly as possible (and kept me updated on the process)-- and when it unfortunately didn't work out she generously compensated me.