E53 battery drain help!

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Hi

I've been having a battery drain issue for couple of weeks now, I changed the battery and it came back. So I done a multi-meter test on battery 0.79 Amps after going to sleep so pulling each fuse and several times resetting the 16 mins wait, frustratingly, I finally found the culprit and the draw dropped to 0.01

The 30A fuse was located in the boot #72

Which protects:

Multi-information display
Navigation
On-board monitor
Sound system

I need help in the next steps to zero in on the issue.

About 2 weeks ago I was driving along and the speakers on one side of the car went out like a fader that had been moved, I wasn't doing anything unusual or playing with controls, they just popped off.
Also just before this happened there was some random screeching coming through the speakers even when the radio was off, just out of the blue would come and go with no apparent cause, for about a week then one side of the speakers went out and the screeching stopped.

This was around the time when the battery drain started which makes me suspect the sound system might the culprit.

Addionally I have a Parrot fitted, which functions ok through all speakers. (Rules out blown speakers)

Has anyone got any suggestions of the next procedure of testing?

Thanks!