Hey there - and hello from sunny California to all you New Zealanders! I love NZ, can't wait to come back..
Like many of you, I was looking for a video that walked through the steps to replace the gear. There are some tricky maneuvers, especially when it comes to removing the actuator from the seat frame. I ended up with a free day and created a video that explains the whole repair. The camera's a little shaky, but I think it will be helpful!
https://www.youtube.com/watch?v=DnoW2jGK58M
Let me know if this helped!