Thanks genixia, I will some day get around to having all the features on my empeg. I've tried installing the preinit code before but it never worked out right...
This isnt a major problem as it does disappear after a short time.
The wiring to the empeg is fine, it shares the power lead to the cigarette lighter socket, and I have run a 250W invertor from there previously.
It's definately the presence of the tuner which is making the light appear

Reception sucks on mine too, but I put that down to the really crappy stock aerial on the car. Im still planning to replace this with an amplified unit which uses the heated rear window for it's reception.