Ford Fiesta 2001 Central Locking Problem

[MWalton122]

I've recently acquired a 2001 Ford fiesta, and the only issue is that the central locking only works from the passenger side door. Twisting the key on the driver's side produces no sound and does no action, yet it works fine on the passenger, which I think rules out fuse problems as after consulting the wiring diagram there appears to be only one fuse. Does anyone have any ideas? I'd rather fix it myself than have to take it to a garage.