I,ve got a German fire bus and you can see the different shade that have been used to touch up over the years.
The m plate on mine says that it was done in RAL3000. and i have just got some Rustoleum to tidy up some dodgy bits.
Worth checking this out as its easy to get hold of. I have cut back original paint with wet and dry, rubbing compound and t-cut to bring the colour out and the match ain't to bad bearing in mind that Red is real bad for fadding... Hope this helps