We have a 6 months old A3 S-line and have had a problem with one of the keys not operating correctly. On one occasion the steering lock would not disengage and the info consul was going up and down together with the radio turning on and off. Audi service said that they had not heard of this before. They did find a software mismatch and changed the key batteries but could not assure us that this would not re-occur and to carry both keys in future! Anybody with a similar problem?