Actually, somebody suggested in another forum that the glove box light stays powered for about 15 minutes which would serve very well.

The only trouble is I still need an instant kill switch for those occasions when I'm parking up.

Also, I don't know if that 'timed power feed' is available in the center console (I've tapped into the mobile harness). If it is, then I still need the kill switch. The trouble is, the only way to signal back on again is Key1.

The glove box solution might work if I can make do without the kill switch and turn the screens off by hand - that sucks. It'll drive my wife mad, and she'll demand I revert the change to the "off by key" default.