Risked removing the head unit in the 3.2, reworked my aux feed so that it exits the 2013 unit at the rear and down into passenger footwell. Then routes to drivers side so I have an headphone jack feed, near the light switch for my usual mount position.
Means I can junk the Bluetooth adaptor, and just direct connect.
Also fixed/replaced the cracked mirror glass. Connection for heated elements different though, will have to replace those before the winter.