I was surprised to see lots of rust stains coming from the angle bead. I do not understood why they don't use plastic on externals? A few coats of rust inhibitor will hold it back.

Aluminium Wood Primer is solvent based primer containing aluminium pigment suitable for use on all types of softwoods and hardwoods, inside and outside, especially those which are highly resinous. It can also be used as a sealer for aged creosoted or bitumen coated surfaces, or as a first coat when using Aluminium Paint on timber where a two coated aluminium system is required. Great for south facing areas.