Assuming the external metal cladding is bare galvanised steel, it is clean, dry, sound and prepared as detailed in the technical data sheet you could consider Rust-Oleum PVDF Primer followed by Rust-Oleum Mathys Metal Cladding Topcoat.

This can be mixed to many RAL, NCS or BS Colours in a semi gloss finish.

Regarding the brick walls, we would need pictures of the area in question and more information on what you are looking to achieve. 

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