Audi A4 TDi Avant Auto (2006 model with Auto Lights)

[Little Mac]

I have a slightly unusual development with the auto lights fitted to my car. On the light switch (always left on auto mode) the 'auto' symbol has started to flash and then goes out altogether. I have checked all lights and they appear to be working okay. Does anyone know what might have caused it to start flashing? When I rang the local Audi dealer where I bought the car they didn't appear to know why it should flash - and instead suggested I take the car in for a diagnostic - for which they wanted to charge me £80+vat for the privilege . Anyone got any clues why it is doing it? It's worth noting that when I first turn the ignition on the auto symbol lights up normally, then flashes (as if warning me of something - which I assumed would be a bulb failure) & then goes out altogether. The other symbols on the switch continue to light up as normal. Any help appreciated.