Ancient Central Locking Dying

[Aduki]

Hi everyone, sorry if. This has been covered somewhere else.

Our Central locking appears to be dying, or at least that's what it sounds like. If I try locking it from the drivers door, it does it very slowly and quietly (sounds like old Walkmans who's battery was failing). The passenger door just locks and reopens immediately, like one of the doors has been left open, and again it's very quiet and slow.

Any ideas/ advice/ solutions greatly received

Thanks in advance.