they did it on purpose mate - they probably did some dodgy work fixing the parkers, and in the process, damaged the headlight housing.
but since u have an aftermarket headlights - they gonna milk that fact n not take any responsibility!!
sorry to say this. but unless u have pics of "before" and "after", ur not gonna have much of a chance the dealer showing sympathy.
holden know jackshit about the astras. wat chance would they have on aftermarket components, expecially something like angel-eyes!!
i've tinkered with the insides of my angel-eyes, n i know how delicate, tight n frustrating it is in there!! i wouldn't trust anyone else to work on it.
anywayz, hope u find some good news. fingers crossed mate.