I think because Oz is a smaller market it's easier to guarantee them deliveries when they are producing less during the switch over period. I've not seen talk of moving M3 production to Germany, not sure it would make sense as China is closer to the other major RHD markets.If you can wait up to 6 months then I would sit tight for the new model. If you need a car before then I'd get whatever you can get your hands on now.
If you are able to buy "quickly" (e.g. cash) you could wait and be fastest-finger-first. I've been one of the first recipients of new models because when the actual order book opened I placed my order immediately (and I did not hold a prior reservation). Folk who had made a reservation, and assumed that was the batting order, were disappointed.
Why are Oz getting a RHD date prediction and UK not?
I'll be getting it through salary sacrifice so can't move quickly and wanted to get and finish the contract before my mortgage renewal in just over 3yrs so want to order sooner rather than later so I can at least have fun with it until the mortgage rate jumps for me!
Going to my local Tesla centre next week to have a test drive of the RWD to make a final decision (providing Octopus EV are still accepting orders!)