Agree with
@rags , caravans plus have always given great service to me especially when I'm on the road and want a part yesterday, general plumbing bits can be sourced from Bunnings, Mitre 10 etc, globes, cable etc I find places like autoelec on Ebay and another place the name escapes me to be great, both Australian, proper australian electrical shops not a chink warehouse in the burbs....... Caravansplus has parts diagrams for most units so makes it so much easier.
For bearings, brakes, springs etc other than the local bearing or brake shop I have also used for various bits these 2 joints,
https://www.couplemate.com.au and
https://www.alltrailerspares.com.au
About the only time I used a dealer for parts was at Watsons at Coffs for new roof vent after hail storm, actually was a good price and since I wanted it NOW was very happy but normally steer clear of dealers.