OK, I went out to my car this morning to start the dreaded commute and upon unlocking it the rear drivers door refused to unlock. have tried several times since but no joy.... Any ideas on what's caused this, yes it adds to the character but I would like to fix it !!!

 

Sounds like the lock solenoid has frozen.

It's a simple fix but just make sure you keep an eye on the "door open" sensor and how it's originally installed.