We had a great stay over a week-long trip to London! We stayed during a warm week in June and the air conditioning worked great. The A/C units are not in all bedrooms but the staff brought in extra fans. Speaking of - the staff is very attentive!
The location is very central and has several Tube stops within walking distance, as well as a Sainsbury's grocery store down the street.
The building is on a busy and loud road. If your group is all heavy sleepers, you will be fine (however, light sleepers may have a tough time - ear plugs recommended)!