It was a very good experience.Luis was really helpful with us and he answered very fast all my questions about how to find the flat,the keys.
The room was clean and nice.The only thing I would recommend to improve is the mattress,if you have back pain it's not very comfortable.
In any case I recommend the apartment of Luis and Zdenka for a good stay in London: reasonable price,good location in the city and very nice apartment.And if you have any problems,Luis is always available to help you.