Aw, poor wee boy. I would have loved that route, especially the big boulder! Scrambling can be scary, but if you lean forward and hold on with your hands when it's really steep, you should have no problems. I would not have taken the steep route over the barbed wire though - that looks like certain doom!
About 15 years ago I used to volunteer with the Loch Lomond Park Rangers, and we did some pathwork. We sometimes worked from massive bags full of rocks which had been dropped by helicopters. I'm not sure about slabs though - they might get broken if they were dropped from above.
I think I'll need to take a holiday in Yorkshire soon - those walks look great!