Finally solve my issue and thought I'd share it with everyone, first some background.

I was having an issue with camera where when the car was not started the picture from the camera was perfect, however once the engine was running the picture was all garbled and unwatchable. The camera was connected to the positive/negative on the reverse light. Initially I thought the problem was with the voltage as my multimeter gave me a reading of 17v and the camera specs specified 16v as the max. So I built a 12v voltage regulator and attached between the camera and the reverse lights, this helped but did not solve the problem.

Solution
How I fixed the problem was with this 10a noise filter from jaycar -

10A DC Noise Filter (Improved) - Jaycar Electronics


I connected the green wire to postive of the reverse light, the red wire to postive to the camera, I connected the black wire to negative on the tail light and I left negative to the camera disconnected.

Now I have a perfect picture. I hope this info helps some one else.

Cheers