Driver's door not unlocking properly

Hi. Have a Lag III 1.5 Dynamique TomTom which I bought new in Oct 2010. Now all of a sudden I can lock the car by pressing the driver's door handle button once or twice or I can just walk away or press the button on the card once or twice and the car will lock as it should. When I return I hear the car unlock as I put my hand round the driver's door handle and every door unlocks except the driver's. I then have to press the unlock button on the card once or twice and that will unlock the driver's door. Just wondering, before I take it in and spend money, is there any sort of "reset procedure" that might sort this out?

Thanks