Main Building, Courtyard Walls, Stable and Gatehouse Blocks, Admiralty Compass Observatory at Ditton Park

The Main Building, courtyard walls, stable and gatehouse blocks of the Admiralty Compass Observatory at Ditton Park were rebuilt after a fire in 1812, incorporating some remains of an older house. Constructed between 1813 and 1817, the building was designed by architect William Atkinson, a pupil of James Wyatt. It features a cement-rendered brick exterior in an early Gothic Revival style, complete with turrets and crenellations. The main building has an entrance courtyard surrounded by stables and gatehouses, all situated within an ancient moat.

The entrance facade consists of a three-storey central section with three windows that have label moulds above them. A central door is flanked by "Gothic" windows with two centred arches and is bordered by turrets and plain two-storey wings that each have one window and crenellated parapets. The garden front showcases a full-height octagonal bay window with a Gothic cast iron balustrade on the first-floor balcony.

Inside, the ground floor gallery features a heavily modelled, vaulted plaster ceiling, while the entrance hall has a beamed plaster ceiling. The main staircase is adorned with a fine cast iron Gothic balustrade. The entrance courtyard is enclosed to the north and south by 17th-century brick walls and 18th-century brick stable and gatehouses, which have rendered buttresses, plinths, and architraves. These structures were 'Gothicised' in the 19th century, and the central towers rise above a large four-centred arch. The stables include a wooden dock turret.