Landrover 90 drivers lock wont open

Hi there, I am renovating a 1993 Defender 90 and have beeen working on the locks, none of which worked when I got it. I replaced the 2 barrels, the door lock buttons and the latch on the drivers door. The passenger door now unlocks and locks perfectly but for some reason the driver's door doesn't. At first it managed to open the lock right at the end of the key turn range but now it doesnt seem to have enough force to open it. It feels like I need to tighten something up but not sure what! Any ideas would be ver helpful. Thanks

Defender you cant unlock? Usually the other eay round with security. Try the defender section, someone will be more helpful there.