I worked out the problem today. The LMIC_PI-master code frequency list for rm915 are incorrect for Australia.
All the 915 frequencies listed in the code are all for South America I had to use a spectrum analyser to pick it up. Which helped me find the conflicting code and check against where it should be.
As a quick test I compiled the code using the CFG_eu868 and commented out the CFG_us915. I then left all the code in except swapped out all the eu868 frequencies from the lotabase.h and replaced them with the correct ones for Australia starting at 916.8mhz on the first channel and bingo.