DONE!!!
Went to Jaycar and we did some testing. The guy figured that that particular resistor was probably a fusible resistor, designed to be the first thing to blow (rather than your LED's).
Anyway, bought the resistor's designated 'RR0524'. These are a 10 ohm resistor. For a brighter light, use 2 of these in parrallel or a single 5 ohm resistor. Unfortunately, I don't have anything to compare how bright the 10 ohm resisitor is as they havent worked since I got the car.
So there you go - $500 for a brand new one, $250 for a secondhand one, or 0.38c to repair your own....