1:18 Englebert Tyre Decals

I'm trying to find a source for 1:18 scale Englebert Tyre decals in white. I have a number of Ferrari racing models representing the 1950s and 60s, many of which were equipped with Engleberts. Exoto seems to be the only manufacturer to reproduce Englebert tyres with appropriate markings. However, I have only found one decal sheet, years ago, that included these tyre decals for a 250 Testarossa - sadly now out of production.
Any ideas greatly appreciated.