Not sure about the screen, maybe you need to change the index code to Zafira and not Astra H.
As for the AUX, the CD70 may need to be modified to make that work.
There are a few How2 on the internet.
The GPS aerial is a bitch to do, run a piece of fine cable or a bit of wood beading through the roof lining and the tape the aerial lead
to it and pull.
Gav
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