Hi Mat,
Hope youve solved your problem by now, but heres a few thoughts if you havn,t.
I take it that you can't get the fridge to light up on gas.
If you think its just air in the gas line, then this should purge by simply holding in the control knob for about 15 seconds. I would suggest that you purge excess air from your system first by lighting your gas hob first.
If theres still no flame, or the burner "pops" and then goes out. Its more likely that you need to clean your burner and flue of dust and debris which can collect when sitting. ie the problem may not be an air lock in your line, but a dirty burner or jet.
One word of advice. dont use a pin or hard object to clean your gas jet, it will wreck it.
Best wishes
David
davec, July 2009