MADAM – The naïve/primitive engraving is probably by the hand of Roberts, the porter, whose handywork can be seen in the entrance lobby. It’s a marquetry panel veneered in ebonised wood and bone. It is a dead ringer for the engraving on the seal and is dated 1736.
There is a pair to this one, namely Ruthin Castle about 20 miles away.
This particular panel was shown on Antiques Roadshow about 10-15 years ago and was examined by John Bly.