[Ultimate Green RS]

But are the Hella units that go internally into the headlamp cluster available for sale. I do not see them on the market...unless you know otherwise.

Personally i'd rather spend the extra money and get the correct unit. OEM Hella units aren't 'that' expensive. I'm surprised, considering how much people spend on other areas of the car, that more don't go down the replacement route than fitting in aftermarket replacement projectors etc I was lucky with mine in that one headlight had recently been replaced when I bought it, then whilst under warranty, the bi-xenon shutter failed in the other. It was replaced with a new unit too

 

[Ultimate Green RS]

It is still very pricey though, don't know if the Ford one costs lots more.

I was referring to the headlight as a whole - The OE manufacturer is Hella and if purchased as a non Ford part numbered part you receive the same headlight just with the Ford logo removed - looks like it's melted off after production