Described in the 1950 Military Installations Closed Areas document as "Camp at the junction of Causeway Bay Road and Tung Lo Wan Road. Surrounded by a fence."
Described in the 1950 Military Installations Closed Areas document as "The area south of a line joining- points 655946, 656947, Guard Room, 656948, 657947. There is no permeter wire."
The remains of a Royal Navy Coastal Watch Station can be found on Port Island. Amongst others the remains of a pier, a mostly complete concrete path leading from there up the hill, a small concrete water tank and a concrete platform are still there.
Part of the path is seriously overgrown, the end of the path is so overgrown it can not be found. Most of the path is in fairly good condition but sections have been destroyed by nature.
This document describes the camp location (thanks to Moddsey for the link):
Quarry Camp
Map Ref. Hind 1008 3rd Ed: 365161
The building is mentioned in Pauline's Post:
[...] the Hankow-Canton Railway Building on Middle Road just off Nathan Road.
and in these comments:
It was built originally as an hotel, was at some stage taken over by the army and used as some sort of headquarters, and eventually housed the Resettlement Department in the 1970s.