[2] A third structure, a brick building in the centre of St John's Street known as the Yarn Hall, was completed 1575, rebuilt in 1616 and then remodelled in the neoclassical style in 1629.

[2] The design involved a symmetrical main frontage with five bays facing south down St John's Street; there was a colonnade with Tuscan order columns on the ground floor and the central bay featured a doorway which was flanked by full-height Corinthian order columns supporting a pediment.

[2] A fourth structure, an ashlar stone building on the south side of Wine Street now known as the Old Town Hall, was designed by a Mr Lawrence in the neoclassical style and was completed in 1752.

[2][4] The building was largely used as a market hall: between 1785 and 1787 it served as an arsenal for the Royal Wiltshire Militia and, while the current structure was under construction, it was very briefly used as a venue for council meetings.

[2] The new structure was designed by Thomas Baldwin in the neoclassical style, built in ashlar stone at a cost of £6,416 and was officially opened with a grand ball on 2 November 1808.