With the help of a couple of beers, it was a straight forward exercise. The only difference was that as I had pushed the plastic fitting in too far, I had to remove the nuts that hold the drive to the gimbal housing completely. Supporting the bottom of the drive with a jack, we used the hydraulic rams to slide it off and hold it in place while a bit of bent coat hanger was used to pull out the plastic fitting. The hydraulic rams then pulled the drive back onto the gimbal housing. Couldn't be easier.
They are quite noisy though when running in gear, both the same. Kind of like no oil, but I imagine they wouldn't be in gear without oil. Guess it will be much quieter in the water.
Thank you Martini and Biffer for your help. If you ever come to Sydney, you will have a boat and skipper to explore Sydney Harbour.