The small section of the folding rear seat on my 1998 Land Rover Discovery 2 TD5 was not locking into the upright position correctly and it also required significant force to push it back.  I thought some lubrication may fix the problem but unfortunately it didn’t.  There was nothing else for it but to take the seat to pieces and find the fault.  The following photos were actually taken during the re-assembly of the seat, but I have displayed them in reverse order to show what should have been the disassembly.

The plastic foot was unscrewed and the screws holding the plastic side panels on were removed.

The bottom panel was removed by pulling out several plastic plugs.

The rear panel was removed by prising it off the seat back.

The headrest was removed and the plastic caps pulled off the top of the seat.

Several metal clips were remove that hold the cloth to the frame.

The rear of seat cushion was unclipped from the frame.

The wire seat springs were released from the frame.

A number of plastic pins were removed that secured more of the cloth.

The foam cushion was lifted off the frame.

There were 3 pop rivets and 2 Torx bolts holding a plate underneath the seat, these rivets were drilled out and the Torx bolts removed.

The spring clip off one end of the square drive rod was removed by tapping the end of the rod with a hammer to drive the rod out.  The rod was then pulled completely out of the mechanism.

The Torx headed bolts were then unscrewed to release the cover plates off the lock mechanisms.

The main locking components are solid pieces of steel coated with plastic.  The plastic coating on the left side one had been damaged by forcing the seat into the upright position.  I used a sander to removed the damaged plastic and swapped this component for the one on the opposite side of the seat.

These photos show the left and right locking mechanisms with the components in the above photo removed.

The cause of the fault turned out to be a bend in the steel component in this photo.  This component attaches to the pull strap that is used to release the seat for folding.  The bend must have occurred through over enthusiastic pulling on the strap.  The bend in the component caused it to hit the side of the slot it fits in, this stopped the strap dropping to the lowest position for locking the seat back in place and allowing the back of the seat to return to the upright position.

The was a bit play in the hinge mechanism which could have caused further problems with the locking mechanism.  I decided to grind a small amount off the length of the hinge bush in the photo.  This removed the play in the hinge.

In this photo I was straightening a plate that had been bent slightly.  This plate is part of the interlock mechanism that stops the back lifting until the seat is locked down.  This is the plate that had caused the damage to the plastic coating on the components in one of earlier photos.

Once re-assembled, the seat folding mechanism began to operates as it should.