Talk to a lawyer now and ask them what they think your chances of success are. The fact that the Member said the by-law was valid, that it had been breached and that NCAT was able to rule on this is a pretty strong position to start with in my opinion.
But a competent, experienced strata lawyer will tell you straight off if it’s worth appealing on that basis. Call our sponsors, Sachs Gerace Broome and say you’ve come from this website and they’ll give you good advice.