Thanks both...........

I expected the Ice>Link to draw 0mA with the car on standby, but if I'm going to leave it for any time (more than 1 week) I'll now disconnect the cable to the actual PCB.

The dealer actually now thinks the BMW 'Professional' car phone system is the issue as there have been problems with these systems if anyone sets it to switch off after the car has been turned off. A TSB was released to dealers in the UK at least telling them to change the default from 30 mins to zero. According the the dealer the phone system has a habit of keeping the car awake if the time is not zero and this draws 300mA - which will kill the battery.

Battery tests indicate that mine is actually OK, but they have found a fault with the starter motor (drawing too much power), the Mk4 SatNav (keeps losing the GPS lock), and leaking power steering hoses!! Good thing it went in for an end of warranty check!!

Cheers again

__________________
Me:
Current: 2011 E71 40D Vermilion Red/Beige Nappa

Wifey:
Current: 2012 R80 Countryman SDX Green/Cream