You dont need to take it apart just need to twist seat frame as its been twisted by incorrect use kneel on seat facing the seat back and push the side nearest to the door while pulling the other side so as to twist the frame slightly then try if seat works if not twist slightly more if it still not work try twisting it the other way after a bit of twisting one way or another you will usually get it working
Peugeot master technician, October 2008
