Australia is an extremely high cost country compared to the UK. Public transport is expensive and terrible. Toll roads are everywhere; you can easily spend $30+ going to and from work a day on tolls.
Property prices in Sydney and Melbourne make London look affordable. If you want to live near the beach you'll be looking at central London prices for at fairly decrepit houses surrounded by backpackers hostels and/or rundown 1970s tower blocks.
The health system is semi Americanised; if you don't have health insurance you get an income tax surcharge, unless you are of low income. Emergency treatment is free but just about everything else you pay a lot for. I paid $75 for antibiotics for my then 3 year old; that was for government subsidised generic medicine.
Most goods have an enormous markup, the 'Australia tax', that means it is often 10-20% cheaper to import goods from Britain or America including postage than to buy it locally; it is cheaper to fly to LA, stay overnight in a hotel, buy a copy of Photoshop there and fly back than to buy it in Australia. On the bright side there is currently a A$1000 limit before import duty or GST is payable on imports.
Australia is about 10+ years behind the UK on online shopping. There is no Amazon or equivalent major online retailer. Many online stores, especially IT ones, charge a credit card surcharge in addition to their high prices.
Economically Australia is slowing down dramatically with the recent collapse in iron ore prices and the imminent closure of the car, and component, industries. However, property prices are still going up 20%+ a year
Don't forget the Australian PM is an idiot of a Sarah Palin level.