I'm thinking best britannia is just one of the many names that are given to the alloy best known as nickel silver. As for the age I guess it's from the late 19th century to the early 20th. I base that on a spoon I found in a corner of a field behind where I live where the previous citizens of my town would dump their junk. Just about everything I find out there dates from the late 19th and early 20th century. The style and shape of this pattern of spoon have been reproduced about 400 years now, so the pattern and shape of an old spoon won't be the best indicator of its true age.
