All in all 3/5. The apartment is more like a dorm. The bathroom needs attention (tub should become a walk-in/stand only shower, sink area needs to be expanded, linoleum needs to be ceramic tile). The floor boards are loose and have some raised nails. The bed and pull out couch are sub-par.
Cromwell street is NOISY! If you have the windows open you will be woken up by emergency vehicles and motorcycles/souped up cars.
The location is AMAZING! The tube, buses, restaurants, and tours are all there! Museums in walking distance.
The amenities are great - dishwasher (we didn't use), washer/dryer (amazing and saves on luggage), as well as stove/utensils/cookware/dishes. We ate out for 95% of our meals but if you wanted to save and prepare one or two meals a day at home, you could definitely do this.
Mr. Williams is a kind and responsive host, immediately addressing to our texts. He even hooked us up with a UK outlet converter for our laptop/phones.