You’re on the right track with this approach. Fundamentally, you need to give the dealer (and manufacturer) the opportunity to put things right. That means giving the dealer access to the vehicle, even though that’s obviously inconvenient for you. A switched on dealership will, where possible, offer you a replacement vehicle while yours is being worked on, too.

Only when the manufacturer and dealer have told you there’s nothing that they can do should you approach the ACCC or other statutory body with your request for a refund or a new vehicle to replace the one that can’t be fixed. While ever the dealer is making an attempt to fix things, it’s wise to give them the access to do so.

For what it’s worth, the problem is likely to be something to do with the car’s body computer which is playing up and not allowing the central locking to work, while also allowing the battery to drain. What looks like a faulty battery can often be traced back to a body computer problem, particularly when the central locking is involved.