We had a couple of hours spare so we took the dogs up to visit the secret (well, secret-ish) bivvy cave underneath Cnicht (aka the Welsh Matterhorn). The cave is actually a big pile of huge boulders, with smaller boulders filling in the gaps to make a hole big enough for one person to live in luxury or two people to sleep in cramped positions on lumpy rocks...
http://www.originaloutdoors.co.uk