You can raise the validity of a vote with the chair before or during a meeting – and every General meeting should be prefaced by a register of whpo is thereand entitled to vote, including any proxies they may hold.
Off the top of my head, you have 28 days to challenge the validity of a vote via NCAT but even then you would have to show that the outcome of the vote would have been different if correct procedures had been followed.
In short, you could have a meeting that failed to meet any of the basic criteria for conduct of a general meeting but if the outcome of the votes would not have been altered had all the conditions been met, then a challenge would probably fail.