Ok, well that didn't help at all, I backed the screw in and out a bit at a time while moving the handle and the thing is stuck good. To top it off the lock retaining ring also fell out while I was jiggling the handle and now I am completely stuffed until I can get the door skin off to put it back in place.
Looking at the mechanics of it there is simply no way to move it more than that few mm as it's restricted at the front by the pivot point fouling the door skin and at the lock end it is held by a plastic spring loaded mechanism - which I also tried levering out the way with no luck.
Have watched videos of it being done, read the manual, looked at guides and pictures and mine simply will not move in this manner.
Here is what I am talking about - this is as much movement as I have after messing with the screw over and over.
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