It's a while since I dealt with the ivy covering the back of the shed.
As the little narrow passageway behind the big shed is also perennially damp, mostly due to the perennials growing through the roof, then that needs dealing with too.
The first picture is after half an hour's chopping. It was even worse when I started!
As we hack, the chimney emerges. I've never seen this before. It's the old chimney from when the bakery was working, so was last functional around 1999. Not surprisingly, it's badly capped off with a bit of corrugated plastic sheet.
This might get the top sawn off neatly, and a sloping breezeblock top added, with a little bit of side ventilation to stop damp.
This might be the cuplrit for one of the leaks. Someone has walked on the plastic corrugated roof boards in the past.
So what's to do? Replace the plastic sheet with the spare asbestos cement boards I already have? (still fragile) Buy some new plastic? New plastic-coated steel? Make another green roof? It's a bit dark at the back of the shed (North wall), so the sedums might not be too impressed and I don't want to give the ivy and brambles an easy foothold.