UK on an Australian Working Holiday Visa

I am a UK citizen currently working and living in Australia on a 417 Working Holiday entry permit.
I am wanting to visit Shanghai in June for 6 days then travel back to Australi. I have read somewhere that I need to have 3 months left on my Australian entry for when I return however my Australian entry permit expires in July. I don't want to pay all this money for flights and hotel, apply for it and then it not get granted. Any advice would be most helpful :) Thanks