Turing’s ‘Eureka’ moment in the bar is strictly for dramatic effect. In the scene, Turing realises that guessing a piece of the message would help eliminate billions of possible settings from the Bombe’s work, speeding it up by an order of magnitude. In fact, the Bombe was designed around the concept of cribbing which was already being used for manual breaks into Enigma. The story about the German operator’s girlfriend, Cilly, is true and was of great help. It’s also true that Y Station (Wireless intelligence radio station) operators had German counterparts who they could recognise by the way they operated the morse key. This would allow, as stated in the film, for them to identify weather station reports and get a head-start on the settings for the day. And yes, a lot of German operators signed-off with ‘Heil Hitler’, so the last ten letters of an Enigma message were often known.