Most body shops can plastic weld something like this. Try and find a small independent guy

Sorry bicarbonate of soda not baking powder.

Engineer Andy i offer this tale of woe.

A while ago we had a mk 1 Outlander, the car never endeared itself despite its amazing handling and roadholding even if it was ugly as sin, even running on LPG (importers conversion) it drank far more fuel than the measly performance justified, worse then the Forester but at least that gives genuine sports car performance for the fuel used.

The mk 1 had serious issues with headlight lenses crazing no amount of polishing could fix, these became apparent even as warranty was expiring but Mitsi failed entirely to offer any sort of help to affected owners, and new headlights were £350 a side, none to be found used as they all do that sir.

Now then, aftermarket light units, i never did find left dip aftermarket so in desperation bought right hand dip and blanked the lenses off where needed, to be fair the light pattern was pretty good certainly better than OE, but that was the only thing going for them, they fitted literally where they touched and were made of the most horrible plastic known to man, absolute junk, due to mishape i couldn't even consider grafting the new lenses onto the old light units if i carefully cut and plastiwelded the things, all in all an exercise i shall never repeat.

I'd be extremely wary of anything to do with lights being offered for sale on that site.