I bought a second hand 2017 2.0TDI DSG Superb Estate last week.
Drives amazingly, but if I leave the doors open for maybe 15-20 minutes, no key in, the battery loses the ability to turn it over.
The battery was replaced 3 years ago by the AA when they recovered it for a fail to start breakdown - Bosch EFB 70AH.

There is something whacky with the SOS Emergency Call thing, amber triangle immediately on start up but SOS button itself shows green.
Now I also have EML amber on as well.

So a few questions:

1. Is the SOS module dragging the battery down, and can I find out if that is the case?
2. Is the EML potentially illuminated due to something unhappy with low voltage?

Sounds like the battery is failing. Do you have breakdown cover with the AA /RAC? If so they’ll come out and check it.

14 minutes ago, numskull said:

Sounds like the battery is failing. Do you have breakdown cover with the AA /RAC? If so they’ll come out and check it.

Just been poking around, it has an EFB fitted, but Google says it should be AGM?
Also there's a Halfords garage round the corner from me: https://www.halfords.com/car-repairs/car-checks/free-battery-health-check-PRODUCTBATTERY.html