Kera – hopefully that Special By-Law was properly drafted to among other things make Owners responsible for the maintenance, repair, and replacement of these externally installed hotwater heater tanks, and that it was passed as a Special Resolution at a General Meeting of the Owners Corporation (not at an E/C Meeting) where at least 75% of those voting did so in favour.
Of course that SBL is still not legal unless and until its Registered on your Plan’s Strata Title by NSW Land & Property Information.