Millsy, I needed the same ones for my Bugs Bunny pinball machines etc, you can buy them from any auto parts seller who specialises in auto parts strips etc.
What i did, was went down to my local 2nd hand car dealer, and asked for the name of the dude who does pin striping and car door strips etc etc, and he gave me the name for a mobile guy who runs out of a van and he had rolls of it in all different sizes.
I am sure every city has a dozen guys like this, otherwise check out ALL your car supply parts places, and even a few local panel beaters for cars who buy this stick on stuff all the time. Hope it helps. !
