G'Day, With the console cover removed, move the T bar from P to D and watch how it operates the switch just to the left of the T bar - the T bar has a pin that sticks out and engages with a slot in the switch....it's this pin that needs to be bent slightly. You need to have someone watching the reverse lights, then slowly move the Tbar till the reverse lights come on and note just which way the pin needs to be bent.
Once you watch how it works you'll figure it out. If the reverse lights do not come on at any position then it's the switch that needs replacing. Good Luck.