I've had three rattles over the last couple of years that sounded like they were coming from the nearside A pillar area. One turned out to be slack in the nearside rear seat latch, cured with a block of plastic foam squashed between the seat edge and the seat back-stop just below the latch. The second turned out to be the passenger seat plastic side moulding tapping against an internal structure, again cured with a plastic foam block ( cut from a large car cleaning sponge ) wedged between the seat side moulding and the lower B pillar area. The third rattle, although it sounded like it came from the A pillar area, I traced to the nearside front fog light ' lens ' which rattled against its surround over bumpy roads. I cured this by rolling up a short length of black PVC insulating tape, flattening it and poking it longways between the ' lens ' and the surrounding trim at the top left corner.