Biege belts back in, reeled back fine, here they are:
I did the tractor test with the black seatbelts, just trying to get the video up, but the end result was that both belts broke.
Nonetheless a very unscientific test of seatbelts

:

both identical, one was washed the other wasn't
the unwashed one broke like this:
the washed one broke like this:
The belts were connected to the front bumpers of 2 tractors, the parked one had the handbrake on and a trailer on behind it, while the other tractor was reversed back in its lowest gear with 4 wheel drive engaged.
It will show up better in the video but its hard really to notice a difference, both broke but there was a lot more tension put on they were made for.