We noticed that all the HARS aircraft had the Australian flag on the RHS of the fin facing the wrong way, e.g., this F111. Is that normal when painted on an aircraft?
Yep - prefectly normal. It should be as if the flag was flying in the wind of the aircraft.

I"m glad to see that it is done correctly as it's one of those things that irritates me - like when people hang our flag, they just turn it 90 degrees and forget to "flip" it to keep the mother country's standard in the top left.