Kerri – apart from putting-up a Member of your Executive Committee as the Owners Corporation’s “nominated point of contact” on its Strata Management Agency Agreement and with its Insurer, which it appears has been done, your problem is a difficult one when an Owner is so determined to by-pass the “system” – and they succeed!
If as you say the Strata Manager, Insurance Company, and Fair Trading prefer to have one nominated point of contact with the Owners Corporation (O/C), then perhaps make sure that the above is formally in place, and advise your errant owner in writing that any further costs to the O/C that arise consequent to their personal representations to any of the above will be at their cost.
Maybe advise the Strata Manager also, as that may additionally dissuade them from engaging in cost-creating activities with the rogue – just in case she won’t pay-up.
By the way, passing-on those costs as I’ve suggested is a bit of a bluff, but I’ll bet that your O/C will only need to send one invoice to get it’s message across; even if she arcs-up and refuses to pay!