Thanks for the replies...
However, I don't want SD card, USB stick, iPod, or even 'virtual CD changer' functionality (!?!)
Nor do I want to control my device from the head unit, or non existant steering wheel controls...
Nor do I want to pay £80 or so for some box manufactured in China for no doubt tuppence.
What I do want, is a simple block connector to plug into the back of the head unit, that gives me a cable with a 3.5mm socket, to plug my phone into.
Preferably made by a good guy on here, and for a fair price!
Can any 'cleverer than me' person do this..?
Here's hoping ;)