Under the provisions of Australian / New Zealand Standard 3500.4 the fitting of a properly drained “safe tray” below all newly installed / replacement hotwater tanks is compulsory in all situations “where water leakage / spillage from that tank could cause damage to property”.
If a safe-tray is not installed, then any warranty provided by the manufacturer of the hotwater heater does not cover any consequential property damage, and if the provider of any contents insurance sends an Assessor to inspect the damage then that cover too will be void.
It’s good to see your acknowledgement of the efforts of Fire & Rescue, but I have to say that the paid services of a Locksmith would have been a much more appropriate option!