ROMI and OzCuda - The belts are standard issue New Zealand Safety belts, every country has standards so I'm not sure if they'll be the same or not. I would presume so as all belts have to function correctly. Give your local vehicle testing station a call and find out where or who can supply/install new standard belts.
They don't fit on the stock location and do not retract away so they do hang there but we set ours up on the same angle as the seat so it hides 85% of the belt. Plus when you're driving that can't be seen as you are wearing them (obviously). They are not an issue with passengers getting to and from the rear, they simply give them a push to one side and hop in.
I agree with you both, they retract which is a MAJOR upgrade from factory originals "stop ya dead in ya tracks" feel. One of the best upgrades we made to the car by far. Sorry I couldn't be any more help.
The photos below of the system are during restoration. We painted the base seat belt mechanism covers black as we did with all the interior screws and pieces etc, not correct but better than factory appearance.
You can see Dave in one photo blacking out the seat back panel screws........
Cheers,
Carl