If you spray some Bradex easi-start down the inlet it should fire for a brief period weak spark or not if everything is setup correctly. Not something I would advocate normally but in extreme non start situations might help. Sounds as if you have "hit the wall" as the marathon runners would say. I can offer advice on this forum but without being there its difficult. Maybe time for a "fresh pair of eyes" Sometimes they will see something thats staring you in the face but you just dont see it for looking. Otherwise take a step back and then work thro all the possibilities methodically. Don't assume anything -check it. Check as much as you can visually is everything moving as it should. It sounds trivial but sort of thing I mean is ---can you actually see the rotor arm rotate with the distributer cap off. things like that. One thing I would deffo change is the rotor arm and possibly the cap. They may look OK but any leakage to earth will drastically effect things.
W204 C200CDI Estate