67 and 68 Castle Street including rear wing, and part of The Castle Theatre (adjoining rear wing of No 68)

67 and 68 Castle Street, including the rear wing and part of The Castle Theatre, is a timber-framed building likely dating from the 16th to 17th century. It stands two stories high with an attic and cellar. The ground floor is finished in colour-washed brick, while the upper part is tile-hung, featuring alternating double courses of plain and shaped tiles. The roof is covered with old tiles and has two dormers with lead casements on the right side.

The façade includes two four-light mullioned and transomed casements, with the lower lights altered on the left side, a central late 18th-century sash window, and a 19th-century angular bay on the right with three intact sash windows featuring glazing bars. This bay is elaborately framed with slender shafts supporting a cornice and hipped roof, along with a panelled apron on the first floor. To the left on the ground floor, there is a bowed shop window in the Georgian style. The central entrance has modern glazed doors that replaced a pair of panelled doors, one of which had a 17th-century frame. The right side of the building features a restored wide curved bow with a delicate enriched cornice. The upper part of the building slightly overhangs the ground floor and is supported by early 19th-century scroll brackets at the right corner and an adjoining doorhood. Inside, there are flat arched brick fireplaces and signs of timber-framed construction.

The rear wing is partly timber-framed and partly built in a style from the late 18th to mid-19th century, with brick dentil eaves and a red brick front. Part of The Castle Theatre is a timber-framed structure that was originally a granary and connects to the rear wing of No 68 Castle Street.

All the listed buildings on the east side of Castle Street are part of a group.