Seems I've come across what my research so far indicates is a British naval issued (HS9) Lemania monopusher chronograph with a sterile dial. Of course I found this without a key component - the movement. Research also suggests if this is a correct case and dial, it should have a Lemania 15 CHT. Can anyone confirm this?
Very nice and an early one, 15CHT is the correct movement. You might have good luck sourcing one if you post on MWR. https://www.mwrforum.net/forums/forumdisplay.php?2-Main-Forum