The flat is exactly how it looks on the listing. It is located on the very top floor (4th floor) of the building. You do have to use the lift (aka elevator) that only goes up to the 3rd floor and then walk up the stairs (about 10 steps) to your flat. The stairs are narrow but it's really not that bad unless you have A LOT of baggage. There are business offices on all 3 floors but there aren't that many people that works there. The offices were closed most of the time and I only saw 2 people working the whole time we stayed there. The cool thing is you have the whole building to yourself once everyone is gone plus the place is secure. You need a security key in order to get it and a security button that you press in order to get out.
The place is in perfect location. It was a block away from the busy Oxford Street where you will find Bond Tube Station, shopping stores, Wafflemeister which is a MUST try, a minute walk from Food Hall (a.k.a food court in the States) that is on N Audley Street, a minute walk to Mark and Spencer (across the street from food hall) which is a clothing/shoes department store, and just outside to the right of the building is Starbucks that opens at 08:30. There are a lot of restaurants that are also within walking distance and more coffee shops.
Overall, it was a great experience.