partner B9 RD4 Aux ports

[Timmo]

hello hive mind,
ordered a pair of aux cables for our cars , fitted mine in my c2 RD4 and validated it on lexia no problem, poppped out to fit the wifes in the Partner, couldnt get the plug in, so looked properly and there is already a plug in the aux socket, has 3 wires that are nicely twisted together and go into the loom, so logically i removed the insert from the White plug and popped it into the second socket on the back but lexia would not configure it??
i had configured aux 1 when i was out clearing the codes from the egr failure and replacement recently (lovely job that was!), it shows on the source list as input 1, but i have no idea what the plug in the socket does??? could it be parking sensors?? i have not seen an aux socket anywhere in the car to make me think its already there.
can the 2nd input be validated with the first one done?? she's out at the mo but can nip out and grab some pictures when she returns if required??