Staying at Tessa's was a very good experience.
The place feels like a home and had almost everything I needed. Tessa had very helpful maps and a socket adapter that show she is prepared for visitors and these were really useful to me. The kitchen has everything needed since Tessa lives there (aside for a microwave maybe but one can do fine without it). The best thing was that as I arrived, even though it was a bit late (approx. 21:00) Tessa sat with me and gave me a lot of advice and answers for some of the sites I wanted to visit and other plans I had in mind.

The flat is on a 5th floor which can be a bit tough but it's located great for it's price so it is definitely worth it. Tessa is a great person and I recommend her flat as an option for staying in London.