"Last Chance Harvey": which London Marriott?

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Marriott must have dropped some money on the filmmakers of Last Chance Harvey. Dustin Hoffman is shown several times checking into or staying at a Marriott in London. Then, his daughter gets married at Grosvernor House. Given the scene where Dustin drops off his luggage at the Marriott, then goes to the Southbank with Emma Thompson, I would think he'd be at County Hall. However, Ambassador reported in 2007 that a scene from the movie was being shot at Maida Vale Marriott. Does anyone know which hotel was used?