The former Milnes' Orangery, formerly the Unitarian Chapel Hall

The former Milnes' Orangery, now offices, was originally built in the late 18th or early 19th century as an orangery for Mary Bridget, Dowager Viscountess of Galloway. It was later converted to a school by Westgate Unitarian Chapel in the mid-19th century.

The building is constructed of stone ashlar and stucco, with red-brown brick to the rear. The roofs are covered in Welsh slate, and the chimneys are stone. The original central block is set back and angled to Back Lane, and is extended by a parallel range to the rear, with later wings flanking the main structure. Access is now via these flanking wings.

The design is neoclassical, in the ‘Adam’ style. The south elevation features a five-bay arcaded central section, which was the original orangery, flanked by two smaller ranges of five bays each, slightly set back. The central section is framed by engaged ashlar columns with feather capitals, supporting a frieze of garlands and paterae, topped by a dentil cornice. Stone arches are set between the columns; the central arch is glazed with narrow glazing bars, while the flanking arches have stuccoed infills, each containing a hornless sash window with glazing bars and a stone sill. A modern door has been inserted on the right return.

The stuccoed flanking wings are divided into bays by pilasters, supporting a plain ashlar entablature, a dentilated stringcourse, and a blocking course. The left wing has a modern central door, flanked by four recessed hornless sash windows with glazing bars and stone sills. A small extension in stone with a flat roof is located to the left. The right wing is similar to the left, with a door inserted into the right-hand bay.

The north (rear) elevation is mainly brick, showing later additions with segmental headed windows, recessed sashes with glazing bars, and stone sills. A hipped roof with two stone stacks sits within the rear central extension’s valley.

Inside, some sets of window shutters remain. The right wing has a coved, groined ceiling.