its up to you but,
- secret things still cost cash (probably even more than none secret ones)
- hiding that sized fleet requires you to be a totalitarian state (that can close off areas/citys)
- if you are the above everybody will not trust you and arm themselves in case (and treaty's break down)
just IMO its your AU so carry on, they are looking nice.
JSB
Actually now I think about it, I have decided that Rossiya will inform America that they are rearming but not England