I’ve been trying to identify this item which looks like a base plug but of course could be something different. Measures about 1 3/8 inches in diameter, fine threads on the outside, two holes for a spanner, one screw, and a central hole with several smaller holes that lead to the opposite side. I’m assuming it’s ordnance related but maybe it’s part of a large optics or instrument. Recovered from the Courcelette battlefield. Any ideas appreciated.