Looks like it is just visible in the bottom right corner of image 1 in post #158.
I did try to remove it but it was absolutely solid in the ground and it wouldn't budgeLand marker, 'this belongs too' or entrance sign. Is it by the West/East drive entrance?
I'm amazed it's still there when the rest has gone. That concrete and tarmac are newer, so workers have worked around it at some point.