Hmmm, based on that and what look to me to be ex GW cast iron gateposts I still haven't got the foggiest
But looking at the relatively wide road and entrance I'm guessing somewhere on one of those obscure china clay lines that sit between the Cornish main line and the Newquay branch?
No - that happened when someone folded the CORNWALL baseboards up to take to the BEST TOURIST DESTINATIONS IN THE GALAXY exhibition on Vircon 5 back in 1987. They should have made them removable