White metal RN buttons

[Guzzman]

I'm sure this topic has been discussed elsewhere on the site recently but I can't find it, so please excuse me for raising it again.

I have some RN ratings buttons in my collection which apart from being in white metal are absolutely standard ratings buttons - plain rim, lined background, crown over anchor. I have examples with both King's and Queen's crowns. I even have 'silver' anodised examples of the Queen's crown buttons.

As I say apart from their colour they are perfectly normal ratings buttons. They are NOT Admiralty Constabulary buttons. Does anyone know who used and wore them? I'm sure I read somewhere that they had something to do with QARNNS but I can't find that reference again either!

Any help would be appreciated.

Pete