The main gps documentation at http://reat.space.qinetiq.com/gps/ is not reachable.
From e-mail from Fan Lei: "The servers at QinetiQ have been switched off temporarily as they are being moved onto new hardware." Once the servers are available, we plan to capture a backup of all documentation currently served there, and import it to the production GEANT4 Web site.
Site is now on.