Rob, I have a lightning trigger, but I've found that most of my best shots are captured without it. I simply set the camera up on a tripod, aim it towards the storm, set the focus on infinity, use a high ISO, usually around ISO800, set a shutter speed of 30 seconds and an f/stop of f/8, and hope for the best. This way, I'll get multiple shots or lightning bolts in each frame.
Many nights, I end up just deleting everything I took, but some nights I'm rewarded with stuff like you see above. Only problem is sometimes if the strike is too close or too big, it'll overexpose the shot, which sucks when you know it was a sky full of lightning, and the image is unrecoverable due to being so blown out
I do hear that Australia has some amazing lightning, so I look forward to seeing some of your images