I have fine cracking to a headlamp lens that does not penetrate the outer surface of the lens. Perhaps 100s of very fine cracks. Has anyone any experience of this. If so, has it been covered by warranty?

Can you upload a picture of it? Is it the same on both sides? I think the dealer might try to blame it on user neglection if both are the same and you have stone chips etc. (even though it may be a poor material choice by the manufacturer), but if only one headlight has is it sounds more like a warranty case.

Might have been hit or pushed at some point.

 

I've also seen when beam blocking tape or stickers are used for driving in Europe, it heats the plastic and causes this crazing.