I assigned Hugo to work on filling in any roofing holes with sealant and tek screwing down the leading edges of any loose sheets on the roof.
Meanwhile, I inserted a pop through the temporary gutter and plumbed it in to the water tank.
I also attached end stops at each end of the gutter.
These are just made up of scrap pine with some primer applied and copious sealant squeezed in to the joint.
This should stop large volumes of water running off the roof and dumping at the back door.