This watch has the code for Royal Navy procurement (0552), but
does not have an issue number or year engraved, which means it
probably wasn't issued through regular British military channels.
The engravings above and below are likely personalized
engravings of the original owner.
The Falklands War
The Royal Marines of Charlie Company, 40 Commando raise the  
Union Jack during the recapture of the Falkland Islands from
Argentine military forces.
Cyma Royal Navy

Case Diameter: 42 mm
Case Height: 12 mm
Case length: 47 mm
Lug Width: 20 mm
Movement: 7 jewel ETA 955.122
quartz, hacking
Case material: Stainless steel
Crown: Screw down.
Bezel: Uni-directional, indexed w/ 60
Water resistance: 300 meters
Vintage: 1994

I’ve been able to learn little about
this watch, as very few of this variety
seem to exist. Similar to the current
British issue dive watch from CWC,
this CYMA diver has a British Royal
Navy procurement code engraved
on the back, but no issue number or
year. The case is military style with
fixed strap bars.