I don't see how cockney's having sex in the street in whatever suburb it was makes that suburb bad. Surely its the people who are bad, I believe there is no such thing as bad place/area, just bad people who live there!
I think you have will now have a negative view about all of Australia since you've decide to move back to the uk, and good luck with your move. Get over it move back and move on!
I'm almostly also certain someone has a bad/strange story to tell about any area anywhere in the world, I have a few thats for sure, both about Australia & the UK!