A8 - W12 - Road Angel

Help - just bought new A8, wonderful car - bought road angel to spot speed cameras but even with aerial extension cannot get consistent signal through the inside of the car - tried various positions only one that works is wedging aerial between glass sun roof and the inside sliding cover - works but ugly - any suggestions ? ...Thanks Andy V

Just in case anyone else falls foul of this. 8's have a heat reflective glass that I believe stops the signals too! External aeriels are normally req'd for SatNav's etc in the 8. I have just bought a Garmin 300T that works 98% of the time without an external aeriel....