Two colleagues looked at the pictures. Nobody has signed a physical judgement. I still have the cover, thankfully (and its identifier).

Ask quality to examine it under the agreed appearance conditions. Keep any damage location with the part identifier. Then you can ask whether the images reveal that feature consistently.

Quality found a small scratch near one fixing hole. The large bright line people labelled is elsewhere. They have recorded both the actual scratch location and the rejection decision.

Does the camera show the real scratch after reseating?

Our reference lesson once used a huge reflection because it was easier to see than the actual defect. Very clear teaching, wrong lesson. I'd keep the physical cover available when explaining whatever imaging arrangement you choose.

Liam, not every time; glare masks the hole area in some views. Ravi Bennett, I'll keep the cover for handover too. We need another imaging comparison before it's a dependable example.

Has the holder been checked for repeatable seating? If the cover rests differently after each replacement, record that before attributing all of the image change to the lamp.

Fixture designer found the cover could rest on two different contacts. Revised seating is proposed, still awaiting a repeat capture session. Thanks Ravi Allen for asking; our lamp discussion had swallowed the fixture question.

Please post those captures' result. Interested whether the actual scratch stays visible with the revised seating.