Well if it it any help to others, I will post how I did it. I went and asked the local holden guys how they reach it, and they took pity and let me watch one they were doing there and then.
The left side pre cat it easy, as you can reach the plug, but the right hand plug is almost on top of the trans. They just put it on a hoist, undo the rear cross member, get another guy to pull down on the trans really hard and reach in from the back of the trans and plug/unplug it that way.
Easy, well sort of easy once you see it done.
Hope that helps someone else.