Four fixing points per seatbelt. Two on the roll-hoop and two on the floor,
Load spreading and strengthening on the floor anchor points is provided by a couple of substantial steel bracket plates, and the upper belts simply clip into the eyebolt on the hoops. But I did make a 2 mm rubber washer to firm up the fixing and firm things up; I also put a drop of locking fluid on the thread too.
Painted the steel floor brackets black and lined them up to drill the holes… Quite straightforward to fit; and I did line up the “eyes” to be tangential to the belt fixings. Also, I needed to think about how to weather-seal the holes in the floor… (not that I’ll be driving in the rain or through puddles; apparently Cobra drivers don’t do that), but it needed doing. So for this I liberally filled the holes with silicone then, when the bolts were tightened, excess silicon squished out and all was sealed…
Used M12 penny washers on the inside of the cockpit to further strengthen the floor fixing points. No need for anything more substantial because there will be no force exerted on this point in the event of a crash, all the forces need to be absorbed by the plate underneath.