unknown makers mark, also unknown metal

[ummedia]

I have a hevy silver coloured plate which is fully stamped on the back. At first I thought it was just epns but it is very heavy the problem is I have looked everywhere but cant identify the marks on the back. If snyone can help I have uploaded a photo of them at

http://www.ummedia.com/plate.jpg

I am very sorry if I am in the wrong forum as this is my first post here dont be too mean just shove me in the right direction. I'll soon learn

any help greatly appreciated

ummedia

[Neruda]

The latters around the central shield EPBM stand for Electro-Plated Brittania Metal. Brittania metal was basically a superior pewter popular in the latter 19th century for silverplating. My guess is your piece is English - possibly Sheffield.