I wouldn't worry too much about the "legality" of using a scanner. Let's face it your average local plod would have no idea and the people who would are quite happy to turn a blind eye. If not then the first thing they would do would be to ban them from manufacture and sale to the public. And to have a real good purge why not go to any airshow or busy airport. Could fill a few busloads with spotting "criminals" in no time.
Come on, apart from Greece maybe has anybody ever been locked up for using a scanner?