Luronium natans looks similar to my untrained eye.
Found these in a small pond in south wales...thats south wales UK not Australia haha. Sorry guys, but i think i got everyone on a wild goose chase as should have said where i got these from.
Luronium natans looks exactly what i have to my eye as well. The downside is if it that its classified as a rare plant and illegal to take from the wild. Ill just do what comes naturel and act dumb. Ill see what the plants do in the growing season, and wherever they flower or not for further identification.