You think Quinton Hazell make parts? They buy them in.
Oh, and I've had some *very* bad experiences with QH parts, so I wouldn't trust them as far as I could throw them.
Incidentally, go to any Alfa forum regarding the 156/147/GT and they say that buying aftermarket suspension parts is a BAD idea, and that you should stick to the OEM FGA (which are made by TRW) parts. Having compared the two side by side with a few different aftermarket components, I'm inclined to agree. The shagged set of top arms on my 156 had been changed a few months before I bought it, and yep, you guessed it; they weren't OE.