We are in Shropshire. The roof is a single pitch of about 5 degrees, and on a single storey sunroom facing southwest, originally stables. The rest of the barn is brick 2 storey.
Aluminium expands/ contracts about 5mm per meter ( I was told) hence the special sliding clips, and the panels are 5 meters. It's not a huge area and accessible. I remember reading on GBF about someone's bad experience with a standing seam roof and condensation so was primed, and keeping a closer eye on it. But the corrosion was entirely unexpected.
The area of plywood deck to be replaced is mostly above the wall, which is timber frame. The roof is, from the inside, plasterboard, intello plus vapour barrier, 9x3 joist with warmcell between, 50mm foil faced pu insulation, 18mm exterior ply, Permavent Eco membrane, then the Vieo roofing.