Congratulations! There is no storage under the seats, technically at least... The battery is under the passenger seat, and the Quadra Lift motor is under the driver's seat, if you don't have Quadra Lift you should have a empty hole there but isn't exactly the easiest to get access too as you have found out. The easiest way is just to pull on it from the front, straight up. But be careful the thing is held in by plastic tabs if I remember right, it isn't designed t be accessed all the time.