E92 330d relentless brake light warning

[technogogo]

Well my gorgeous, wonderful 07 reg 330d has finally developed a minor issue after 18 perfect months... One night a few weeks back: 'bong' left rear brake light failure. I reversed up to a wall and sadly the report was true. Later when I got home, reversing up against the garage door, I noticed that the brake light was working again. I checked the bulb next morning - which is really easy, tool free exercise - and noted the filament was intact. There was no issue with the bulb holder unit, moisture ingress or loose wires that may cause intermittent fault. But since then I still get the warning bong on engine start even though the brake light works.

Is this simply a fault that needs to be reset at a dealer or suitably equipped indy? or would the car detect a simple bulb change and cancel the alarm automatically - meaning that the continue 'bong' indicates a problem with the broken bulb detection system?

I have walked through the iDrive menus but could not find an option to reset the fault.