Repair Galvanize shed leaks, add flashing at wall

Looking for someone experienced with roofing or metal shed repairs to fix water ingress where a galvanised shed roof meets a higher block/rendered wall. The junction is approximately 10 metres long. I believe it needs proper wall/abutment flashing fitted rather than just sealing with silicone. There are also a few small holes/old fixing points in the galvanised sheets that may need patching or sealing, and I’d like the existing roof fixings checked while the work is being done. Looking for a proper long-term repair from someone familiar with galvanised roofing/flashing. Budget is for labour. Materials can be supplied/reimbursed separately. Photos available showing the roof and wall junction.