Thanks to all for your interest and assistance. Here is the text which is with the moderator ...
Dial - ROLEX OYSTER printed on single line between 10 & 2. Arabic marking with ? Fueille blue steel hr/min hands. The words EXTRA PRECISION are shown around the top of the second dial which may have a 'Moderne' blue steel second hand. The words SWIS MADE are shown at the bottom of the dial.
The back is engraved with a serial No 31785. The case has not been opened to examine / find any inside markings / hallmarks.
The watch is currently working but has not been serviced for decades, if at all.