'Naval Service' is not a new term and includes, as pointed out, the those in sworn Service to the Navy, but I also thought it includes the Royal Fleet Auxilliary - quite a fleet in its own right. The The RN Maritime Auxilliary Service (who used to operate the 'black and buff' tugs and similar) were contractorised about 15 years ago. Their last base was HM Yard Pembroke Dock.