well, all the wiring for the said cold pack is in the car. all thats missing is the switch (down next to the headlight heigh adjuster) and the actual heater units, ie the heated glass in the mirrors, and the heater thing that is on the inside of the front and rear windscreens.
the circuit works on a momentary switch, i have no idea how long it activates the heaters for (well its actually just power to the relevant devices) but it just worked on my car when i plugged it all in! i was quite surprised when i saw the plug for the switch taped up and it fitted in the plug and lit up the light!
ill take pics when im back in the country. from memory it had a brown surround for the wire, but im not 100% on thata