I think I may have solved my problem. After doing all the things that you did (plugs, coils, injectors, INPA, endoscope) I finally took the two right hand side vanos solenoids out and cleaned them (as you did) with carby cleaner. I also checked them by connecting them to a 12 volt power source and putting a small screw driver into the bore. When connected they clicked and the screw driver moved out of the bore about 10mm to 20mm (see youtube). There may still be a bit of hesitation under heavy acceleration but I honestly can't remember how the car ran originally. No matter how hard I try I can't generate the 29CC and 29CD errors that would always occur.
Given all this I would say that vanos solenoids are definitely the issue.

Update:
False alarm. Solenoids were not connected properly and as a result I ended up with a car that ran a lot better but with 2A80 and 2A85 errors (vanos activation intake and exhaust). I am now back where I started, 29CC and 29CD errors and a misfire under acceleration from low revs. Back to the drawing board.