DaveAll Does this help at all? My 2018 Panda has the uConnect radio, USB socket by the phone cradle and a second USB socket in the glovebox. Alongside that is the Aux input (this glovebox unit was dropped from late 2018 onwards). There are, I think, 5 wires connected to the AUX socket (the usb part has a separate usb plug going into the back). These are probably the same five wires I can see (but not get a photo of!) going into the back of the head unit. You can sort of see them in the attached photo.
The pin-out wiring diagram for that head unit socket is on the top of the radio itself, also pictured. Its not very clear, but I think the left most three read AF Earth, AF L and AF R - and that would tally with the appearance of this aux input lead listed on Amazon, where the three left-most pins are used
https://www.amazon.co.uk/Becker-Adapter-Cable-iPhone-Player/dp/B00EDJE6KE - but what the other two wires do I don't know (maybe they are connected to a switch within the Aux socket that tells the head unit a plug has been put in?).
Edit - just realised: those other two wires are labelled AUX DET(ected?) and earth. So yes, I assume the wires on pins 16 and 17 are connected to a swtich within my Aux socket that tells the radio there's something plugged into the socket. From what you say in your first post, I'd assume this switch is normally closed, and so connects the 'DET' pin straight to earth when there's nothing plugged in, as so turns off the AUX option)
The Mic connections are at the far other end of this same plug - you can see them in that pin-out diagram (again blurred, but reads Mic + and Mic -)
The only other connections on mine (apart from the power, speakers and this third plug in the diagram) are the other end of a USB lead, and the aerial connection which are towards the other side of the back of the radio unit. This photo (found online) shows the rear of my radio - is this the same as yours?
https://eurofrance24.com/media/cata...1cbc/6/c/6c5b1f256284472a9ff6d9cea1f230ff.jpg