The following text is from the original listed building designation:
TF 3140 DOVER WESTERN HEIGHTS
685/7/10010 Admin block, Dover Young
Offenders Institution
GV II
Formerly known as: Officers' Quarters, Western Heights. Officers quarters within citadel, now offices. 1861, by the Inspector-General of Fortifications. Red brick with limestone dressings and flat asphalt roof. Gothic Revival style. Double-depth plan. EXTERIOR: 2 storeys and basement; 15-window range. Similar front and rear elevations have deep projecting centre bays, cornice and deep parapet to a former bomb-proof roof. The entrance is flanked b buttresses with a flat 2-centre archway and steps up to a mid C20 door beneath a pair of gun ports and a panel wit the royal coat of arms dated 1861. Windows have paired Tudor-arched lights with 4/4-pane sashes under flat-ground-floor and 4-centre arched first-floor arches, with a mid-point Tudor-arched doorway to the inner elevation with flanking lights, under cross-light oriels with weathered coping to front and rear. Large clasping buttress to the ashlar ends, which are divided into 3 bays, the middle one narrower with gun recesses and splayed side INTERIOR: The entrance hall has a large mid C20 stair, and rooms off an axial round-arched passage the length of the building. The basement contains former stables, stores and water tanks. HISTORY: Formed the quarters and mess for the officers in the Western Heights Citadel (SAM), which was built in the 1800s. The origin accommodation was all in casemates. With its gun ports and bomb-proof earth-filled roof, it was partly intended a defensible keep in the event of the Citadel being stormed. The level of defence is representative of a time of rapid developing artillery and fortifications.
Listing NGR: TR3095840541 - taken directly from source

The battery observation post for South Front Battery was originally built on top of the building but this has now been removed (2)

<1> English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.

<2> John A. Guy, 2013-, Verbal communication from John Guy, defence expert working in the Dover area (Verbal communication). SKE24831.