I put a wanted ad in for an OEM lap belt to match the others that I have in the van, not wanting to mix a modern one if possible, but would also be interested to see if there is a supplier for these. Does anyone make them, or is there somewhere to buy a used one? VWH don't do them.
I think you'll have to find one second hand. Put a wanted ad up, scour eBay but I bet an auto jumble would be best.