Cypher/Crown - Help Needed?

[Roy]

Hi Gents,

I confess I'm no expert where Royal Cyphers are concerned. Could some kind and knowledgeable soul educate me on the crown/cypher combination on this button? I'm attempting to date it. I won't embarrass myself with an opinion at this point.

I've been spending time this morning trying to research this and I think I'm more confused than ever..

Two pics attached of the same button, one showing the cypher and one the crown.

Cheers,
Roy