problem with upvc mechanism, sourcing spare parts...?

[Michl]

On the lock side of my UPVC window ("Maco 97 4", "DKM Gr 5 1800-2350") it looks like I'm missing a couple of small parts and I think this relates to the problems I'm having trying to get the window to shut and seal properly. I compared the lock side with a window that is ok and I can see the faulty window is missing the small metal plates that screw on and numbered 31576 on their reverse side.

I adjusted the cam bolts so that the window shuts more tightly but I'm still having problems. I've just started googling for the spare part but if anyone had any recommendations where to get these (and also what their function is and what might have caused them to fall off?) I would much appreciate it! I've found a possible supplier in Germany so far...

 

[Michl]

As you can see the mechanism splays due to the missing plate that screws on at this location

 

[Michl]

Also, I have a query about adjusting the position of the window sash: I was able to adjust it by turning the horizontal adjustment screw and the allen bolt in the lower hinge, however I couldn't see how the upper hinge could be adjusted. Am I missing something, or is it simply a fixed hinge?