Ask any JAA ATPL exam graduate (many here!). They all have the Student Pilot Route Manual, which includes a pretty comprehensive legend. Most use them for cigarette papers after finishing the Flight Planning exam, as tehy are not much use for anything else - I'm sure someone will send you the pages in the post. Slight problem is they are out of date - the format of approach plates has changed significantly. It is only the layout though, the symbology seems to be the same.