Tomtom 6 backlight stays on - how to turn off?

[Guest munky^^]

I don't think I'm missing anything blindingly obvious, but with TomTom6 (on M3100) the backlight stays constantly on. From a quick google it looks like it's been designed like this, but I think I read that the symbian version has backlight options.

That plus bluetooth will surely wear the battery down pretty quick, and I don't have a car charger.

Any solutions to this?

Cheers