Could you not open the door manually with the key? You say the passenger lock spins, but don't mention the one on the driver's door.
The most common cause of central locking failing in that fashion is a broken wire, usually where the wires pass through the rubber gaiter between the door and the body - As the wires have to flex every time you open and close the door, they are weakened and can snap internally. This is even worse if the gaiter is damaged in any way, as they then rub against the sharp edges of the hole in the door.
If that is the case, you may be able to replace the wire or splice in a new section. I don't know how Skodas are arranged, some cars have a plug fitting between the gaiter and the body so the door can be removed. If so, you should be able to disconnect it and check with a multimeter whether the wires between that and the solenoid are still intact (you will have to remove the door card to get at the solenoid, which will be on the inside of the door shell near the lock itself)