I found the sequence to lock the doors when you drive off which def works on older focus and the mondeo mk3 but not sure about fiesta.

1. Turn on the ignition to position 2 but dont start the engine

2. Lock the door by pushing in the button below the handle, and then pull the handle slightly to reopen it (Repeat this operation three times)

3. Turn ignition to position 1

4. Lock the door by pushing in the button below the handle, and then pull the handle slightly to reopen it (Repeat this operation three times)

5. Turn on the ignition to position 2 but dont start the engine
A beep should be heard

6. Lock the door by pushing in the button below the handle and then pull the handle slightly to reopen again
A final beep should be heard.