E220 CDi Estate rear seat stuck

[Davidwgc]

The passenger side rear seat back will not release and is stuck upright. The release handle pulls up OK and the red unlocked tab shows, but the seat back will not fold down (the drivers side is fine). There seems to be no way to get to the locking mechanism. Is there anything I can do or is it just a case of brute force?

 

[OlafMaxwell]

Common problem and I think it means taking seatback apart. I know there are fixes posted here but it is not such an easy job.