Central Seat Harness

[72s]

Hi - has anyone found a way to safely fit a belt for the center of the bench seat other than the lap belt ?

I have swapped out the three original lap belts for a pair of three point belts on each side but would love to find a way to get a belt back in for the center of the bench to allow me take take another (child) passenger.

As the bench back is too low for a harness to be safely used on its own (the belts would be pressing down on the top of the passengers shoulders) all I can think off is fitting the harness but having the passenger sit on a large child seat/small race seat that would lift the belts above the shoulders. The harness would be holding both the seat and the passenger to the bench.

I've searched around but unfortunately not found a solution so far.

thanks!