Haha Roy, sounds like fun.
To get the King Charles on his cavalier horse under the bridge the roadway had to be lowered by about a foot or so (if you look carefully at the bridge buttresses you can see the undercut and re-enforcement) there wasn't enough clearance so the tires of the trailer had to be deflated, the picture went through with about a 1/4" clearance!
I did manage to get an unofficial tour of the quarry some years ago, before all the untopping work commenced, we got to see everything bar the Cabans, which the quarry supervisor wasn't prepared to show us only letting us glimpse them from the gates!
Better to regret something you have done - than to regret something you have not done.