Victorian? Ring Markings

by Ann
(Birmingham)

Hello

I have a supposedly victorian ring which has a variety of hallmarks on it:

1) WG&S
2) a crown in a box with all corners cut off (gold?)
3) 18 in a box with all corners cut off (18k?)
4) an anchor (which I think is Birmingham)
5) a P in a box with all corners cut off which looks italic font with a curl at the top
6) the word PLAT (platinum?)

My research has led me down a blind path with contradictory answers so I was wondering if you could help?

Many thanks
Ann