Trying to remove a door

[Cowhorns]

I've looked at various threads on here and cant seem to see my door on here.
The external hinges look straightforward but this seems to be more complex. I am planning to remove the black split washer/clip on the left of the picture(arrowed). Its beneath the assembly and looks like it would free me to remove the nut holding onto the door. Is that correct or is there something else I need to do?

 

[angel]

Look for a nut at the top hinge pin, too. If you remove the arrowed clevis pin and move the mechanism away, there is nothing more holding the door.

This door holding mechanism was never fitted on any R4 but its body fixing plates don't look like an amateur fitting. Was your car an ex- La Poste one?