Classifieds here. I sent a complete shell and doorcards to the scrappies the other week!
My car has.also been.listed on eBay for nearly two months. Search for 'breaking' or 'spares', as that's how people list them. Then send them a message with what you are after. If you have a rough idea of what you would be happy to pay, let the.seller know. But if you take the ****, don't expect a response. I've got my Recaros listed for £850 on eBay (will actually take £700, but you have to inflate your eBay prices because they take so much in fees between eBay and Paypal) and have had clowns offering £250!!
I would say eBay as well, just text everyone that has whole car breaking or the part that you need. As Blue_Thunder said, make an offer all the time, as eBay charges are huge, so everyone add them on a listing, but if you are happy to pay in cash and collect the items yourself you can make a deal.
And if you are looking for some expensive stuff like Recaro's, or S4 bumpers etc. you need a luck to find someone who does not know what he's selling and gives for A4 prices. It does happen sometimes. Not for me, but it does. And that wouldn't be eBay I guess, scrap yards, private breakers mostly.