Mmmm.......
As a PPL holder am I required to know what the rules are and how to find them? (or is it an adequate defence to say "this bloke on the Internet told me it was OK?")
The answer to your question can be found in
JAR–FCL 1.080 (assuming it's as JAR PPL(A) that you hold.
You can also find the answer in
LASORS
Mike