Ok - here's a weird one. On your front passenger side seat, have a feel of the side bolstering and frame. The door side of the seat has a frame which comes quite far out ie if you press the bolstering, you can feel it quite easily. However, if you go to the other side (gearshift side), the frame end quite low in the bolstering. ie the bolster has some movement in it whilst the other does not. The drivers side seat is all good. Is it just my car or is this a design thing?