General Doblo rear door

[TDW1]

i have a 07 plate Doblo van with a rear nearside door opening problem got all tthe bits off and can see the arm that spins up to touch the plastci arm of the rod but it does not touch so wont open the door and i cannot see how my local garage reckons the plastic has broken it has not ! is this adjustable i cant see why it's suddenly stops opening everything is free!