Thank you all so much for your good advice! I'll be over there in July, and thought it'll be "summer", I'm a cold frog - I'll definitely be bringing jackets and warmer clothes! (Debated as to whether I should bring my electric vest, just in case.)
Thank you ellasaunt - that's a lovely offer. Always useful to have a local perspective!
Eve - if you're visiting Australia and consider 28 degrees hot (CRUD MONKEYS!!), then depending on where you're planning to travel in Australia, perhaps our winter might be better for you? I'd say July for you, from the sound of it!