I don't think there is an executive or concierge floor as such. The concierge lounge is not on the top floor. While the concierge lounge has no windows (or view), the breakfasts and snacks are somewhat better than the average (with table cloths and place settings at breakfast). I am guessing the upgraded award simply guarantees you the Thames view, but not a specific floor. I'm told that not all Thames view rooms have the Parliament/Big Ben view, but some have only the Thames/London Eye view. You will want one with the Parliament/Big Ben view. These rooms will also have a view of the London Eye. You may want to call the hotel direct to see whether they can block you into one before you leave. The phone number is on the Marriott website.