Private rooms. At The Grosvenor Arms, a Dorset hotel, restaurant and bar, there are also three separate private rooms which can be hired for celebrations, private dinners or meetings. The Assembly Room. Our largest room, which is on the first floor of the building, has capacity for up to 60 people banqueting style. There are few finer rooms at any hotels in Dorset. With huge sash windows and a view out to Shaftesbury town-centre below, this is a perfect venue for a wedding reception or a special celebration. It can also be hired for other events including business. The Restaurant. There are two private dining rooms within our restaurant which can be hired as separate private rooms, with capacity of 12 or 16 guests. For private dinners you may select from the à la carte menu or we can design a special menu for your event.