Me too. Great simple idea to tart up the plastic vehicles. I think we have all of those floating around the house. You are a good grandpa.
Actually the vehicles, with the exception of the plastic Army Men Patton tank are Dinky and Lonestar diecasts, mostly picked up at car boot sales. I just gave them a lick of paint, didn't even have to prime them or strip them. As has been noted the decals are mostly GW 40K from the huge pile of spare decals I have loitering around.
And if anybody knows where those plastic Zombies come from please share. I have a friend I just gave a load of painted 1/32 SWAT guys to looking for a game.
and thanks to you all for the kind words. If you haven't tried something similar, and you don't need kids for an excuse, I can thoroughly recommend it. It has been great fun to touch base with our roots so to speak. I will get the rules into some readable order and post them ASAP.