Been out for a long drive today and used the secret menu on the clima control to monitor the running temp . I used setting 19.2 on the secret menu . For the first 10 minutes the temp did not go above 74 , but the operating dial on the dash showed 90 after 10 minutes of driving .Got on the motorway for 20 Minuites and the temp went up to a max 76 on the secret menu but no higher. Coming off the motorway under engine breaking the temp on the dash did drop a little bit but the temp on the secret menu stayed at around 72-75 . the final 10 Minuites of the journey was in town and a lot of stopping and starting the temp on the secret menu then rose to 87, Not sure what all of this means but I think I may have a sticking or stiff thermostat. I'd really appreciate anyone's opinion on what they think could be going on the car is going in the dealers on Tuesday and id like to get this sorted under warranty if it needs sorting .