If I'm not entirely mistaken, I believe that's a pic of the facia adaptor for the older 8L model. The adaptor for the 8P should be in one piece, that's atleast how mine looks like (sorry, don't have a pic right now).
I used the items in your picture to fit an aftermarket stereo to my girlfriends A3, but it's only a 51 plate. You might need a wiring adaptor too? I had a nightmare sorting the right one-it's got the Bose system-and there are two different leads to chose from-one that uses the standard wiring plugs, or an alternative if you are fitting a head unit with pre outs. Not many of the accessory shops stock them because of the cost (between £40-£60 ) depending where you buy them. Unicar were about the dearest!! Regards. Paul