i found it easier to get the memory in with the rubber guards removed
that video also shows the memory being removed and reinserted once the rubber covers are off — I found it a lot easier to remove the covers in order to insert the memory, and then re-seat the covers once installed.
The lack of LTE compatibility in Australia is due to the historical set of frequencies that the carriers (mainly, Telstra) are using here for it. It's well known to anyone who pays attention to these things in Australia. It's interesting they ship the same model though.