My friend is also from Australia and had the same thing and he ended up getting a retirement visa. He was told that would be his last entry and the next one had to be qualifying for retirement
I have a true sim in Thailand on rolling PAYG and reduce that to 100 baht a month when I leave. In uk I have an e-sim and on a plan with my son who gets roll over data that he uses and cost me £8 a month and is the easiest way for me. I used to use two phones. That was a pain