The place is adequate for 4 people especially for family with younger children. We are a family of four adults but the bunk bed worked just fine. The neighbourhood is pretty close to either a bus stop or a 15 minutes walk to a District/Piccadilly line tube station. A small supermarket nearby as well.
Even if the flat is located on the top floor it's two flights of short stairs so even if you have some bags to carry up it wouldn't be too much of a problem.
Communications and checking in & out are no fuss as well.