My car failed it's MOT this morning, with the main (highest cost) item being that the Driver seat is not considered "secure".

When having a closer look at home, when the seat is in the lowest position (adjustable height), then the seat flexes on the back left; drops lower then you would expect and pushes forward more than it should.. If you sit in the seat and put your weight into the back of your left butt-cheek then you feel it lean a little further than it should.

When I elevate the seat, the flex decreases and basically if i'd set the seat higher and turned up to the MOT they would have passed that check.

What I need to understand is why it flexes so much at the lowest position.. My lack of mechanical skills do not help (but i'm a tryer).. I can't see anything that should dampen the flex, but i don't have a "working" version to compare the seat against to try and spot any differences..

Does anyone have any idea's..

Ford C-Max Zetec
2006
1.8 Petrol
Manually adjustable seat