I have no problem cutting glass up to maybe 4mm, as picture framing is a small part of the business. I've used a Toyo wheel cutter for years, never a problem, but recently wanted to cut some 6mm sheets that had been dumped, broken windows maybe ? Just cant do it every time.
And more pressing, I have a front foglight thats broken, but the structure, reflector, lamp all ok. As you can imagine it is a moulded piece, with the prisms and facets...and really quite thick. 7-8mm at the edges.

It is detachable , has a part number but Subaru won't or cant sell just the lens. Complete unit upwards of 300 bts, and weeks to come from japan or Korea.
I have a selection of old headlamps and fog lights kicking about in the shed and one with almost the same pattern of prisms, from an old Merc, but of course I need to cut out the shape from it. Even the curves are about right. It will do til I find a breaker's that has one.
Tried diamond wheels for ceramic tiles, on the angle grinder, but no go but I'm guessing there's a special bit of kit for this, or a Dremel or similar.

Any tips and ideas?