Blocks 21 and 23 (HQ Block and Rear Block)

Former Cavalry Barracks in similar style to the other 1840s buildings. Long 2-storey range of seventeen 12-pane sash windows (and smaller later? windows); central square stone clock tower with weather vane; hipped slate roof; rectangular stone chimneys. Squared stone, pilasters flank doorways in 3rd, central and 15th bays, bands at eaves above first floor; plinth. To rear, connected by later corridor, a parallel lower 2-storey range. Stone, slate roof, stone chimneys. Squared rubble with ashlar dressings; bands at first floor sill level, and above ground floor windows. Some alterations to openings generally with 12-pane horned sash windows.