I visited Craig More near Crieff on the 5th of May and saw several work men building some kind of cave type construction (wooden frame covered with some kind of concrete) on the walk in, very near the crag. I went again today (26th) and it had gone. There was enough dust about for me to be sure that I wasn't hallucinating on my first trip. Does anyone have any idea why the cave was being constructed and what has happened to it? I'm curious as to what was going on!