I have a rectangular "Last Supper" plaque which measures about 9" x 15", and it is marked in the lower right corner, "Made in England". The back has a ten-link chain, with a circular piece in the center for hanging. This picture is "framed" with the relief being hammered into a 3/4" frame surrounding the picture, and is also highly detailed in all other aspects, and is in excellent condition. Can anyone help me with its age and value?