Hi, this mayvsound daft but I have a 2006 stilo active, the 5 door face-lift model.
I have just found a leaver on the side of the passenger seat, the opposite side to where the back rest adjuster wheel is. This leaver doesn't seem to do anything anything. Any ideas what it is for?

You've just found a great feature! Push the lever down and push the seat back forwards and you've got yourself a flat folding passenger seat!
I love this feature in my Stilo. Perfect for trips to the tip and for reclining the rear bench and using it as a leg rest. I've even camped in my Stilo like this