While I was checking them I presumed, being Light Emitting DIODES, that they would only accept current in one direction...a couple of them would some a little resisance both ways and all of the others had an infinate amount of resisance both ways.
I've had a look at the online Maplin Catologue at 3mm 12v LEDs and they look a bit of a different shape. The ones in the radio look more like mini versions of the bulbs in the interior lamps - the fact that that they accept current in both ways also makes me think this.
Can anyone with a bit more electronics knowledge confirm or not?
Heres a couple of photos:


