Gosport - HMS Centurion then.
Wikipidea says this about a centurion:
"Centurions often suffered heavy casualties in battle, generally fighting alongside the legionaries they commanded. They usually led from the front, occupying a position at the front right of the century formation. They led and inspired their men by example. They also sought to display the skill and courage that got them to their rank in the first place. It's for these reasons that they often suffered a disproportionate number of casualties."
So that'll be why they named the RN's pay and manning office after the Roman officer, because the pay staff always fight alongside the ...lead and inspire...display skill and courage...
Or something like that.