All radios need two feeds. Red=12v battery, and Yellow=Auxillary switch in ignition barrel. To enable use without even using your key, connect both of these wires of the radio loom into the red wire from the car loom. If you have any probs, PM me.
Have a look here: <a href="http://www.cavweb-forums.co.uk/showthread.php?t=4055" target="_blank">http://www.cavweb-forums.co.uk/showthread.php?t=4055</a> (Might have to register)