I was thinking about getting some Headlight Adjusters from eBay, but I'm suspicious. They look like exact copies and they look like they will fail as quickly.

I was thinking of doing some blueprints for DIYers who could fabricate a set with basic tools and materials.

Thin sheet metal, coupling bolts, ball head screws, and some jb weld.

Or go completely cheap with a nut, bolt (with a small head), block of wood, and a tin can. I'm sure it will be way better than OEM.

 

The eBay ones with the metal replacement parts work great. Myself and many other members have purchased them.

Jaguar X Type X Type Headlamp Headlight Repair KIT Adjuster | eBay

I'm sure there are all-plastic ones available, but as you pointed out it would be foolish to replace a failed plastic part with another that would likely fail again.