At great risk to life and limb, six months ago I removed our burglar alarm case cover from its high position under the eaves. Its white paint was peeling off the red plastic so I sanded it down as well as I could and gave it two coats of an all purpose primer. I thought that would be OK for another 3 or 4 years. But I was clearly wrong because it's already starting to flake off again.

This time I'm getting my window cleaner to do it. But that means it needs to remain in place, as removal involves some tricky wire-cutting etc. I'm therefore seeking advice on what sort of paint I should buy for him please? Ideally, after the minimum of sanding (not a nice job at that height) I'd like him to be able to apply it directly over the present mix of primary and the small areas of bare plastic. And not need more than one coat (unless it's terrifically fast drying).

Any advice would be much appreciated please.

Terry, East Grinstead, UK