Longcon

Hi first post here i have tried searching loads of forums for information before posting.

I have a 2006 s3 the stock radio did not work when I bought it. I now have 2 a symphony and a concert. My wiring only has 3 plugs see the pic im sure its meant to have 4 I do have 12v on one of the plugs but I have read it needs 2 is this right? I cannot find a spare plug tucked out of the way so it may have been previously removed.
iam hoping.to get the radio working whilst iam off work do I need to run a extra cable? Is there indeed a power cable missing? Its a bose system. I have downloaded loads of pin out guides but im struggling to find one that matches my car. Any ideas would be greatly appreciated

Longcon

Just to add
my cigarette lighter does not work
Boot only opens off key
Passenger door intermittently opens
parking sensors work when they wish
I have checked all fuses all look good I have just read about removing carpets to get to wiring not sure if thats the same in my case I really don't want to take everything to bits if I don't have to.