I can well believe that, if you really think a shed would be constructed from stone. You should find out about asbestos cement before drilling into it. And you'll need planning permission if people are to be sleeping in it.
We got in the ground early, and just walked into the empty East Bank. Daubed there in paint was "Enter the East Bank at your own risk" - a warning that now applied to the author! I was 17 and yes, like hundreds of others, was on the pitch but near the centre circle. A couple of lads swung on the...