The Post War AAOR at Dover Castle reused the central casemate tunnel of the Napoleonic era that had been fitted out as a Gun Operations Room (GOR) during WW2. This Casemate was shared with the coastal defence GOR and was next to and parallel with the Admiralty Tunnel of Vice Admiral Ramsey, responsible for the Dunkirk evacuation.
The Casemate Level is immediately above ‘Dumpy’ Level which later became an RSG.
The underground hospital and wartime tunnels have been opened by English Heritage as a visitor attraction, along with the rest of the Dover Castle site. More information is available at their website.