This is a rare bird and a rare find indeed!
We have finally managed to acquire a 1980 CWC “fatboy” Navigators watch with rare date model
These don’t seem to be very common at all compared to their non-date brothers and according to Terry Andrew’s database, he has so far only noted 11 of these that have come up for sale out of approximately 600 issued.
Lowest number seen is 086/80, highest number 560/80. This one is bang in the middle at 283/80
These watches are listed under DEFSTAN 66-4(Part 5) Issue 3 dated 19 June 1981 as,Watch, Wrist, Electronic, Navigator, Luminous for navigational purposes. NSN 6645-99-541-7362. As such, it may be used by all departments of MOD except for HM Nuclear Submarines.
The watch came out of a private collection in the UK where it had been sitting for the better part of 30 years since being bought as surplus in the late 1980’s.