WQ Door Lock Problem

[puppy]

Hi y'all
I recently bought a 2008 WQ Fiesta which I love to bits. (don't say that!) All the door locks work fine with the remote. By chance I tried the key in the driver's side door. Turning it to the left locks the car fine. Turning to the right nothing happens. It's as if some lever isn't connected. The car was repaired on the drivers side before I bought it.

Does anyone know if this is likely to need another lock or could it be a missing linkage? Should I buy another second hand lock before taking it all apart? I'm worried that I won't be able to unlock the car if the remote battery goes flat some time in the future. Any help greatly appreciated.