Mercedes Forum - Mercedes Benz Enthusiast Forums - a160 Locks And Central Locking

Hi everyone,
My girlfriend and I recently bought a second hand 99 A160 Classic. We have been having a problem with the locks and central locking. It started with having difficulty getting the key into the drivers door lock to open and close the car. Since then the lock has completely seized. Now we can only lock the car from the boot and often this seams to not work as well. So therefore the internal lights do not go out and have run the battery flat. We now have the lights out so this won’t happen. The passenger door lock seams to have been disengaged and does nothing so to me it seams like these cars may have a problem with the locks they have installed on the car.
My guess is the problem is stemming from the drivers door lock which has seized. I was contemplating taking of the door card to have a look at the lock but the car has door air bags, is this still possible for me to do (is there a way to disengage the airbags).
Also wondering if anyone else has had any problems with there central locking and locks any tips and help would be much appreciated.
Thanks Josh