Brian Gaff wrote :
I thought this was UV damage and could not be cleared without some kind of
replacement?
Certainly another famous French car seems to have this issue.
Brian

Lots of modern car headlights have this issue. Polycarbonate absorbs
UV, which crazes the out surfaces. So surface removal works, but when
manufactured, they had some sort of UV proofing coating. That coating
eventually wears away, leaving the polycarbonate with little
protection. Fine abrasive polishing brings the clarity, but with none
of the original protection, they very quickly degrade again.

Ideally, what is needed is a DIY clear spray, which is proof against UV
to protect the polycarbonate lens once it has been restored.