A work colleague knows that I have an interest in vintage watches (tho only Omega to this point!) and asked me for help with his father’s Submariner. He (father) did some commercial diving and was inseparable from the Submariner. Watch no longer works and has clearly seen a very active life... I’ve made sure that he goes nowhere near a Rolex dealer In the meantime and will get it to a good watchmaker - but hoping for help in identifying it (only had chance to take this single photo) and anything particular that should note for the watchmaker in approaching a repair/‘restoration’? Thanks for any help!