I'm not mechanically minded, but it sounds to me more like a loose trim rattle, rather than a mechanical issue. Check the seats, centre console for anything loose or rubbing together. I'd also check that the rear seats are secured properly, especially the floor mount as they should lock in place with a click.
if that doesn't solve it. take it back to the place you bought it from and get them to investigate it.
if that doesn't solve it. take it back to the place you bought it from and get them to investigate it.
