What sort of license are you looking at? Operating license...mechanic...pilot's?? The JAA is the authority that regulates you guys, and the JAR are the Joint Authority Regulations by which the legislature is enforced by the various enforcing agencies...(Ala FAA here in the US). Contact the JAA website about what type of license you are looking for.
Twinjets...if one fails, work the other one twice as hard!!!