Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

My girlfriend has a w-reg Vauxhall corsa 1.4 CDX 5-door auto. It has started having problems with the doors locking recently. When she uses the key to lock the doors from the driver’s side, it will only lock the drivers door and leave all the other doors unlocked. She then has to lock the car from the passenger’s door lock. But even from the passenger’s door lock, when you try to lock the car, it does not always lock all the car doors, sometimes she has to leave the car unlocked as she can not lock the car. This problem seems to be intermittent, but happening more frequently now.
Can anyone help to try to resolve this problem, what has gone wrong with the car and how to fix the problem?.
Thanks in advance guys

its possilbly got a loose wire the the door connecter by the sounds, but i arnt not electriction haha

update: the fuse for the central locking seems fine. When try to lock the car from the passenger's side lock.. the car locks but sometimes when you take the key out of the lock, all the locks open again..
Anyone know why this maybe happening?