In the jungle not far from Smith Point there are the partial remains of a WW2 camp; possibly for Indian soldiers. All that is left are concrete block type structures and drains. This area was probably where the ablutions were located ie. toilet, washing area etc. The concrete drains lead away towards the cliffs and ultimately the sea.
I have visited this site several times but never saw the inscription that was carved into what was then wet concrete of a newly constructed block. Chris Tremayne, a local with extensive knowledge of Island relics, told me about the inscription and took me back to the area to show me. Rubbing his palm across the base of a concrete block several times to remove a build up of dust, the inscription became clear.

Mohd Mushtaq No 90
Well Come 19th April 1941
A Google search shows that the surname “Mushtaq” is Pakistani. This inscription was made before the 1947 partition of India and Pakistan did not exist. The name and number indicate that the man in question was likely a Punjabi soldier.
The 19th April 1941 date is very interesting. Captain Kinloch arrived on Christmas Island from Singapore at the beginning of April 1941, roughly two and a half weeks before, with a contingent of men that included 25 Indians (Punjabi Muslims). His task was to set up and calibrate a 6 inch Naval P3 gun, set up a fort site and dig trenches and train locals to defend the island against invasion. Was Mohd. Mushtaq one of the men in that contingent? Did he make the inscription when perhaps the ablutions were being constructed? Is he welcoming others or did someone inscribe this welcome for him?
I hope to add more information about this WW2 site in the near future.