Help ! concert h/unit in b7 avant.

I'll try to be brief .My avant was (still is) fitted with a symphont h/unit and disc changer is kput so I got a concert h/unit with code of fleabay which came with the quadlock loom. Now everything appears wired correctly (non bose sys) but when in unit refuses to switch on so I can input the code.so is the head unit knacked or am I missing something,does something need changing/recoding in the vacom for it to power up or have I bought a duff.HELP !
P.S I have sorted the different aerial connecters with the help of audi dealer and srapyard.new double fakra block from dealer and an iso to fakra adapter from the scrapyard just need to know if they should fit a certain way round.

Firstly big thanks to s8craig topman, Just to clarify I have an 05 B7 which was fitted with a symphony (not sure on model dut 6 disc and cassette d/din) and was fitting a concert d/din (marked as concert EU B7 Soul) so should be a concert 11+ which came with an after market iso to quad kock adapter I've now sorted the double power feed issue and it powers up.so now need to srt the aerials.
I've got the correct double connecter block from audi so do I just put the existing fakra into one side and get a iso-fakra adapter and put it in the other,does it matter which way round they go !