Fraser Bond are the leading lettings and property management agents for Sentinel House - London NW1. Sentinel House is an office building on the corner of Harcourt Street and Old Marylebone Road in Marylebone, London NW1. This site is an off site affordable housing for St John's Wood Square development. St John's Wood Estates Ltd is developing the site to supplement a related development, the former St John's Wood Barracks. Planning permission for 41 affordable residential units. Amenities would include a rooftop playspace. The external hard landscaped playspace on the 8th level is.