I have a 2005 2.0 TDCI Focus. In the last couple of weeks I've noticed something odd when I first start the car. I turn the key to start the car and nothing happens-the engine doesn't turn over, random dash lights come on and the speedo needle goes up to 50 mph and stays there (even though the car is not moving!). The trip meter also resets itself to 0. On the couple of occasions this has happened by getting out of the car, locking it, unlock then turn the key again the car starts. I'm assuming electrics, anyone shed any expertise on this? The battery is fully charged and no fault codes showing.

Thanks.