So to the finalise this thread.
I fitted the HU, plugged the USB cable into the back of the HU and low and behold Apple CarPlay came to life.
This confirmed there is an issue with the USB port. Started digging about under the HU for the USB cable next to the DSG gear lever only to find it neatly curled up out of the way.
I can only guess that when the HU was initially installed Apple CarPlay wasn’t available so the cable wasn’t connected.
Anyway connected the van USB cable to the rear of the HU and tada, Apple CarPlay is alive.
You live and you learn.
I fitted the HU, plugged the USB cable into the back of the HU and low and behold Apple CarPlay came to life.
This confirmed there is an issue with the USB port. Started digging about under the HU for the USB cable next to the DSG gear lever only to find it neatly curled up out of the way.
I can only guess that when the HU was initially installed Apple CarPlay wasn’t available so the cable wasn’t connected.
Anyway connected the van USB cable to the rear of the HU and tada, Apple CarPlay is alive.
You live and you learn.