Like the best magazines, this article consists mainly of pictures - as it is nearly Bank Holiday weeking and I am heading off to a Camping Barn near @recoveringacademic's place with friends.   The problem is straightforward.   About 5 years ago on moving to the current house I had a 8' by 8' shed constructed in a corner of the garden which consisted of (perceived) well-packed rubble from many years ago. We used a base of concrete fence-posts laid flat to allow some minimal gi