The thing is, they CAN install these belt assemblies correctly, because there are photos that show them done that way on both sides of the car.
Right side done correctly; belt is flat all the way, no twist, and the cloth tab at the bottom and the blade are pointing towards the seat:
View attachment 26346
Left side, same thing: belt is flat all the way, no twist, and the cloth tab at the bottom and the blade are pointing towards the seat:
View attachment 26347
So it CAN be done because somebody there on assembly has done it, which shows it is NOT supposed to be twisted if the belt mechanisms are installed correctly. This isn't just a matter of twisting the belt around at the seat end, because then the blade and cloth tab are now pointing in the wrong direction, away from the seat. The entire assembly has to be installed in the correct orientation starting with the mount inside the side of the car. If it's installed correctly at that mounting point, the blade and cloth tab will be pointing away from the seat, towards the side of the car, so when the installer pulls the mounting plate on the end of the belt up and through the B Pillar, the cloth tab and blade will then be pointing towards the seat and you can attach the mounting plate to the seat.
This picture shows the seat belt mechanism inside this side of the car has been mounted backwards. This assumes they're using the same mechanism for both sides of the car, and it just has to be turned one way or the other before it's installed. If they have TWO different assemblies, then there is definitely one for the right, and one for the left, and the visual clue before installation is the cloth tab and blade should be pointing away from the seat and towards the side of the car.
View attachment 26348
If ANYONE is doing a tour, PLEASE show them this post with the pictures, so they'll understand what's going on, because somebody there clearly doesn't yet. If the belt has to be twisted to get the blade to point towards the seat, the mechanism inside the side of the car was installed backwards. If there are two different belt assembly part numbers, then there's definitely one for the right side, and one for the left. They cannot be interchanged. Maybe some of you going to Goodwood? Show them this!