Infotainment not working, then flat battery

[Will15]

This week our 73 plate Kodiaq L&K (6 months and 3 days old) had a flat battery and various warnings coming up on the dash when my wife went to start it. Car had been driven home from work the evening before without issue. Fortunately she was at home and VAG roadside assistance turned up within the hour.

Roadside diagnosis was a flat battery, possibly due to a problem the infotainment system.

There are no consumer addons (I have seen another thread in this section where a dashcam drained the battery). 

 

The background for the previous 2 weeks, we had been unable to use the radio, media, or Bluetooth for calls; no sound from speakers and 'volume' green bar didn't move by on screen touch or by steering wheel. Even in Park a warning said sound settings couldn't be changed until car was stopped. Voice control also didn't work. Ironically the car was already booked in for infotainment to be investigated in a couple of weeks. 

 

We have also had an intermittent issue where the speakers would make a loud brown noise for 20 seconds after the ignition was turned off after a long journey, which we managed to capture on video. However the cause couldn't be identified. It's related to infotainment but I don't think it would be related to the this week's problem as it hasn't happened for at least 6 weeks. 

 

Has anybody experienced similar with a flat battery and what was the outcome? I'm always suspicious if I hear from official sources that they haven't heard of the problem before. 

Edited 29 March by Will15