A bit of a delayed response, but I didn't want to ignore it. I do stand corrected on many of those points. I don't agree with the last sentence, but I appreciate the accuracy and will upvote.
For something to be a world series, I would hope there would be teams around the world that represents the sport and compete against each other. For example, in football (your soccer), you have a world cup which has countries from around the world competing, and you have competitions like the Europa Champions League (the best clubs in Europe competing). I think one individual from a country doesn't necessarily indicate country participation.
I think it's because the Australian flag has British flag in the top left corner. The blue part is Scotland, red vertical and horizontal flag is England. The red diagonal is Northern Ireland.
Basically, Scotland want independence from the UK, and probably don't want to be part of that flag, so that is likely why the blue is being placed over the red.