I just called EFI (we got teh 30kWh upgrade through them too). and they have seen a few like this. They say its something to do with the "CAN box" in the upgrade and he's contacting the supplier of the upgrade kit to see what can be done.
We're in Perth too petere and having similar problems. It does seem to be temperature related but also problems with our aux battery not lasting long. A few times in the past if we've left the car locked (alarm on) for a few days, when we get back the aux battery has been "killed". Gone down to...
