It's my old Blaupunkt headunit.

I was unable to get decent AM reception with the tuner kit and the VW amplified antenna system ,so I've gone back to the 2 headunit system so that I can listen to football on Radio 5. I still have the tuner connected so that I can use the Sony Stalk.

I have tried reducing the standby timeout as low as it will go (1 second) but the problem persists. I appreciate that it's not a bug as such, I'm just trying to find a work round. I'm going to pull the headunit and put a meter on the remote amp line (which is what I'm using to feed into the tel mute of the Empeg) to see how quickly it turns off after the ignition is off. If there is a delay I might try putting in a relay that switches it off when the ignition goes off.