Hi guys & girls, I do apologise for adding to this historic thread but having now taken time to address this on my own van I wanted to share what I have found.
The previous threads/comments have all been helpful but what I couldn’t do was in any way reduce the length of that plunger. There appears to be a hard plastic captive retainer that moves slightly but doesn’t appear to thread/unthread. I thought if it did I could then adjust the length and thread it up again. Maybe I’m being too gentle.
Anyway after much huffing and puffing I gave up and went to the door handle outside. Obviously the same issue. Unlock door and handle is ineffective. But by chance I locked it, unlocked it then unlocked it again and the handle engaged. I performed a single unlock and it failed, unlocked it again and it worked. So not a fix but another question. Is it possible that these vans have a double locking setup ¯\_(ツ)_/¯ or is it just that my van is reluctant at first but obliging on the second press.