We had a wonderful stay at Davids place. Although the flat is situated in the very heart of London it was absolutely quiet. The bed was very comfortable so we had a very good sleep. We did not have very much time speaking to David because we went early and arrived late, but he was very helpful and accompanied us the first day to a very good Persian restaurant in the neighborhood.
Usually David sleeps on a sofa but is was broken and so was one of his arms! We felt a little guilty using his bed while he had to sleep on the floor with a broken arm. A really generous host!
We had some problems finding the flat because we did not realize that 50a meant that it was a basement floor with the entrance below street level and that odd and even numbers are on the same side of street. Just look for 49 on the street level and then for 50a downstairs.