Copper / Silver / Silverplate Tankard

Bought this Tankard and would like your thoughts as to Date !!. I believe the Thumb Rest to top of handle is a Solid piece of Silver with an incised initial to it, there also appears to be signs that the Tankard was once Silverplated. 

Here's Thumb Rest.

Anything to see underneath?

Nothing to the base, I'll post a pic of base later when I'm home

The Base as promised