I recently bought a second hand 807 and one of the seats has the same problem. I tracked it down to a cable arm in the side of the seat.
If you need to remove the seat you can reach under it to a bar close up the the bottom of the squab. Push the bar towards the front of the seat and down towards the floor. This will release the seat. Be careful that you don't get hit as the seat pops up!
If you look at the right-side of the seat (seen from the back) there are two plastic covers. Just behind the top of the upper cover there is a clip which you can release with a screw-driver. The panel then hinges out and off.
In the space behind it there is a plastic arm which is connected to a cable that runs down under the seat. This releases the seat when the seat back is tipped forward. The arm on my seat has snapped and there is no obvious way to remove it or fit a replacement.
If anyone knows of a simple way to replace this arm I would be very grateful.
John Mangan, October 2009
