Thanks to a tip off by TFW2005, Cartoon Network Australia has issued a press-release of their summer TV lineup, and it includes the third season of the Robots In Disguise cartoon, on Saturdays from November 5th at 8.30am.

That's the good news (if you have Pay TV).
The bad news is that it only lists 6 weeks, so this third season (or second half of the second season) is only 6 episodes.

For those without Pay TV, I imagine that it should show up on Channel 11 by the end of the year as well.

Transformers: Robots In Disguise
BRAND NEW SEASONS
Saturdays at 8.30am, Saturday 5 November - Saturday 10 December

Get ready for some spectacular Saturdays as the Decepticons and Autobots crash back onto your screen, with the launch of Season 3 of Transformers: Robots in Disguise. Team up with Bumblebee, Optimus Prime and Windblade for awesome robot-powered action every Saturday morning, to ramp up for the rest of your weekend!