Might no be Humbrol at all. It makes sense they use Humbrol for the helmet detail but for the larger area of the backpack they could have used car spray paint in tin. I remember cars of that colour around then.
Off the board a few days and I see Rolf has not only received his helmets but built one already. Just one? I expected the whole lot to be done by now. Don't cut yourself on that uber sharp detail now. Looking forward to the armour arriving.