Audi A3 brake fluid warning light

If its cold (5am in the morning cold) brake warning light comes on,after a while it goes off but makes an appearance on corners/roundabouts until everthing is warmed up then its fine.

Plenty of fluid in res and pads have plenty on also ABS works fine,so..... could this be just a temperature related problem thats not worth worrying about ?

Is it the same light as the handbrake?? If so is it a sticky switch or summit?

bad wires on the verge of going? (remote i know and a pain to figure out)

Thanks guys

The car belongs to a workmate,we have been through the what we think might be obvious and i'm begining to think it might just be the sensors on the pads.
I had a similar prob on a ford some years back and that turned out to be the pad sensors,since the brakes are working fine on the audi and there is no apparent loss of fluid it would seem dap and cold conditions might be the prob.
I'm thinking if the pads are halfway through there life the sensor could just be close and when the pads and discs have warmed a little the dampness may go thus why the prob dissapears.

I'll have a check of the handbrake tomorow.