So after much searching for new old stock decal replacements for the Scapin—including contacting Scapin directly with less than helpful results—I eventually gave up and realised the only way to do these decals made up was to get them done custom.
Although it was a 'restoration' job, apparently a lot of places don't like to touch these sorts of jobs because they represent some sort of copyright infringement, unless you're getting the frame reprayed as well. Bullshit. At any rate, I figured that'd be at the expensive end of options anyway.
I ended up finding a place just down the road that could do what I wanted. In the end I just went with a cut vinyl option which meant I went with a modified design for the steerer tube 'badge'.
This bike project just goes on and on.. it will finish soon. In truth it is basically completely finished.. When the weather is colder (snowier) and stable, I think I'll do a photo shoot in the snow and the process will be complete.