I can only recommend Karen's house. It was nice and located in rather calm part of the London, considering the fact centre is not too far (around 15mins to the train station by foot and 20mins by train to Victoria Station). Karen herself was very helpful and answered very thoroughly for all our questions before the journey. Room was comfortable and organized nicely. If you want to rest after the long day of sightseeing for reasonable price - that is the place for you ;) Also breakfast in the morning is helpful. Thanks Karen!