MF, do click and collect. You dont have to register for an account (although its instantaneous and you dont need ABN or a credit card number straight away).
They are really good with C&C - they were poor to start but really got their act together. Note, do not do more than 2 orders with the same card in a day or it will glitch and you will be charged but not get the order.
Its only 25% off at repco, but not an awful price especially as its a 6L
Some things are autoclub only, you just put your NRMA card number in at checkout.
There system is easy to understand, I would strongly suggest doing it and not risking if they will still be around in stores tomorrow
I am amazed the Fairlane takes only 4L - I am used to tipping over 6 straight into a V6 Toyota