39 and 39a Brook Street and 22 Avery Row

This is a complex building of historic importance, comprising a remodelled 18th-century house to the north, a two-storey link to the south-east, and a two-storey wing aligned north-south containing showrooms at ground floor and a gallery on the first floor, with stairs in the north-west angle.

The house itself is built in brick with street elevations faced in stucco and slate roofs. It rises three storeys above a basement, with an attic storey above a moulded cornice. Three windows overlook Brook Street, including a curved bay framed in panelled pilasters and surmounted by a shallow leaded dome. One bay occupies a re-entrant angle with its ground-floor window converted to an entrance, and one bay faces Avery Row. The windows are sashes with slender glazing bars. A 1927 shop front features Ionic columns to a curved entrance. The elevation to the link block in Avery Row displays a pilastered shop front of 1926 with Gothick intersecting glazing bars and a first-floor Diocletian window. A single-storey entrance to 22A has a panelled door and Georgian-style fanlight.

The garden elevation has a later 18th-century appearance: three storeys and five bays with a mansard attic, built in yellow stock brick with gauged brick window arches, a stuccoed cornice and parapet roof. The ground floor is stuccoed with triple sash windows to the left, probably dating from Wyatt's remodelling. A glazed timber canted porch was added in 1906. The sashes are six-over-six pane, some replaced. The stuccoed elevation to the gallery wing is irregular, with a shallow ground-floor extension featuring an oeil-de-boeuf window, probably early 20th century. An off-centre pilastered bay is surmounted by Coade Stone urns (one replicated). The end bay has a row of casements at ground floor and a tall sash window to the first-floor gallery, with a moulded stucco cornice and parapet roof.

The interior features a handsome open-string stair of 1720–3 with a curtail, column newels, and a ramped mahogany handrail with three balusters per step in alternating twisted, spiral and columnar patterns. The ground-to-first-floor flights have a ramped inner string with raised and fielded panelling and foliate carving to the tread-ends. Remnants of panelling survive in the stairwell passage. The octagonal stair lantern, added by Wyatt, is raised above a glazed pilastered wall enclosing a gallery with a Carolean-style coved plaster frieze.

The ground-floor front room contains a chimneypiece with a white marble surround and Siena marble slips, dating from the 1770s. The rear south-west room, reworked by Wyatt, has a very shallow segmental vaulted ceiling with a banded ceiling border and a chimneypiece with Ionic columns. The rear south-east room features a distinctive neo-classical chimneypiece with slender cast-iron columns. The first-floor south-west room has a segmental vaulted ceiling and banded ceiling border inset with anthemion decoration; its white marble chimneypiece with yellow Siena marble slips and side consoles dates from the 1770s, and the cast-iron grate is early 19th century. The first-floor front room has panelled window architraves, a coved cornice, and a niche mirroring the curved window bay opposite. Above this is a panel inset with an oil painting depicting mythological figures with musical instruments. The second-floor rear rooms retain matching 1770s chimneypieces with timber surrounds and marble slips. The full-height plain panelling of these rooms, while typical of an earlier 18th-century date, forms a cohesive scheme with the chimneypieces and is probably contemporary. The house retains numerous fittings dating from the 18th and early 19th centuries, including moulded skirtings, dados, architraves and panelled shutters. Upper-level cupboards and panelled doors survive alongside modern fittings of generally sympathetic design.

The first-floor ante-room to the Gallery, decorated by Fowler and Lancaster, is painted deep terracotta with swagged decoration. Its walls and built-in cupboards are lined with late-18th-century Italian oil paintings depicting classical and historical scenes, said to have been acquired by the firm for their frames. The Gallery, known as the Yellow Room, has panelled double doors at either end with reeded architraves and paterae ornament. The segmental barrel vaulted ceiling is decorated with banded panels with paterae at intersections, reminiscent of Wyatt's music room at Bretton Hall, Yorkshire (1815). Painted decoration to the tympana, mirror-glass in the blind arches of the door surrounds, and marbled skirtings date from the Fowler and Lancaster redecoration of 1958. A niche on the east wall, originally containing a stove, holds an imported 18th-century marble chimneypiece with an eared surround. The entrance hall, formed in 1958 to serve Nancy Lancaster's apartment at 22 Avery Row, has arches flanked by Corinthian columns.

The building comprises a series of rooms of unequal proportions around a central open-well stair. At ground floor the entrance hall and front rooms now form a single reception area. Above this level, the room plan is largely as it existed in 1823.