Found what I needed eventually, just incase anybody ever stumbles upon the thread -
https://www.ebay.co.uk/itm/Audi-A3-2007-Onward-Car-Stereo-Full-BOSE-Fully-Amplified-Active-Speaker-Lead/201103252759?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Fascia, Keys and Aerial connector are quite easy to find. But the wiring I found above wasn't!
Alot of companies will ask if your system is half amplified or not. If you have the BOSE system like me, then you have a fully amplified system and require the above.