I've got this 6 point harness that I'm putting in my mk1. I've got most of it in all good, hopefully. I've just used the original seat belt mounts for the lap belt, and I've got a harness bar under the rear parcel shelf for the shoulder straps to mount to.

But I'm not sure how the crotch strap should be mounted up.
Do the straps go down to the floor and attach to a point/bolt there? And would it be better to have one or two bolts in there (both straps to one point, or a separate point for each)? Or is it meant to go down through the seat, and then back to the same mounts as the lap belt?
Does anyone have any pictures or suggestions of how the strap should go? I'm just not sure how its meant to be set up.