jag XJ8 2007 back seat armrest won't go back up seems to be hooked on something any ideas ?

 

It may be that something has slipped down between the seat and backrest and

is preventing it from pivoting. I might even be the seat belt buckle.

 

Some (not mine) have a removable panel for a ski hatch. If yours does you should see the matching panel from inside the boot. Could it be displaced?

But more likely, I agree, some loose object fallen into the pivot.

 

so far nothing is stuck will look in trunk (found a dime though!)