[Chadm]

In case it helps anyone else...

At a complete loss, I emailed Bimmercode support about this, who directed me to this setting:

Receiver Audio Module > Expert mode > VSG_WAVE_FILES > change to "file_14"

...to get rid of this annoyance on my G20 330e.

Unfortunately, whilst this did get rid of the VSG sound, it had an adverse impact on the audio function / iDrive system, causing it to crash at startup, resulting in having to revert the setting back to "file_1".

Having another poke around, I coded the following setting, and hoped for the best:

Receiver Audio Module > Expert mode > VSG_FUNCTION > change to "inactive"

And hey presto! VSG gone, no errors, and no adverse impact on anything else!