Viceroy Plate tankard

I have got a 1 pint tankard in Viceroy Plate with the initials NOJ LTD inside a shield on the bottom and on the side its stamped PINT with what looks like a coffin shape with inside it a crown with GR 6 and outside this D30, does anyone know where this may have come from, its age or anything about the company that made it?

You may have already ‘goggled’ it. Viceroy Plate a tradename of the National Silver Co., In business from the 1890’s to the 1950’s.