When i joined the RN in 1985 and become a Submariner i was going to buy a Rolex Submariner, alas i discovered Ladies, Cigarettes and Beer!
You may be aware that the SAS and SBS were issued Rolex watches at one time and those military versions are highly sought after, very collectable and extremely expensive to acquire these days some pieces running into many hundreds of thousands of pounds each, Any sports Rolex (purchased privately) worn on active service that has seen any action may also command a serious premium over a civilian piece..
regards