Hi Roy, that's good - many thanks.
My interest was sparked yesterday because my wife remarked that many years ago, when she was head of outdoor pursuits at a north Wales school, she used to take groups on the through trip from the entrance in the wood/forest and out into the quarry. She was impressed by the standard of the equipping that we could see through the grill - nothing like that back in the day! Times have changed for the better.
Cheers
David