We had a wonderful time at Mercedes place, which is a real house and not a cold touristic apartment; we went there with 3 kids who were delighted by all the available toys and books, and we perfectly accommodated in this spacious flat 4 adults, 2 kids and a baby.
The flat was very clean, with 2 functional bathrooms (both features not very common in London!) and the neighborhood was very quite and safe. Even if not in the city centre, there are very good connections both by bus and tube.