Bongo Fury

hi,
my bongo has a rear conversion,and has two small bench seats in the rear,running front to back,over the wheel arches.i`d like to fit a lap belt to both of these in case i carry any extra passengers.i wonder if i could bolt the two parts of the lap belts to the wheel arches,about 18 inches apart,andf use a plate or large washer underneath to strengthen it?would i need to seal the edges of the holes with anything?i realise that a lap belt is not very effective sideways on,but i thought i`d try it.is the metal of the wheel arch strong enough to mount a belt?
thankyou
jamie

I would think that having lap belts, on a front to rear seat, would cause more injury than nothing at all. There would be a hell of a twist on the spine.

Doubt it would pass a MOT...Seat belts need to be bolted directly/indirectly to the vehicle frame/chassie. Wouldn't sit anyone on a side seat anyway.