Hi Andy, can you post some close up photo's of your watch including the dial with hands (with hands set at 10 and 2 so the writing is not obscured), as well as the bezel insert and case. It would also be helpful to know the first two digits of the serial number.
Service dials were made with tritium and then later with both a "toothpaste" dial that has the appearance of tritium but isn't and a white luminova dial. It would be helpful to see what you have.
Rolex UK do service 1680's and they will only replace what you authorise them to, you won't necessarily have to have parts such as dials and hands replied because of age and if they are original you will want to avoid replacing. I can't answer the bit about waterproof guarantee although others will.
