Maybe we should use "Guardian Office" instead of "Naval Base"? Because they talking about protecting both the girls and the country while the 鎮守府 has that meaning too.
A nostalgic sounding nameA Naval Base... huh?It will be hard if they noticed, but I hope for your cooperationYou should have talked about this matter with me much earlierTaking back a decision is a big drag you know...This might not be the time... but I was one of the humans who treated fairies as subjects for experiments instead of human, you know.