@izzythepush,
True enough izzy, but for much of your more recent history (post Norman say, or at least House of Tudor) England had been something of a cultural monobloc - not withstanding expatriates from the far reaches of the empire resettling in the motherland (not to mention the Irish and the Scots) - it wasn't until the 50s that migration really kicked in - with large influxes of West Indians, eventually followed by South Asians.
Australia has a very short history and has always had a large influx of migrants - weighted towards ex-Englanders until world war II.
There some very interesting cultural historical patterns about not only our attitudes to new ethnic groups but also the behavious of successive generations of original migrants. Children of migrants perform much better at school than the general population, but their children settle back into normal performance. Every couple of decades we tag a particular group as 'social security bludgers' apparently it was the greeks in the 60s - the polynesians more recently.
We thought the italians bought the mafia, the vietnamese/chinese bought the triads round and round it goes until our panic runs out of steam and we get a sort of non-enforced assimilation that is tolerant, or even celebratory of our cultural differences. I'm glad my life has included Macedonian weddings, polynesian hungis, Fijian kava ceremonies, yorkshire pud and sauerkraut.
I don't get the fear for the survival of Australian culture - truth be told I don't even know what Australian culture is - people will say it's a fair go, sticking up for the underdog, egalitarianism 0r looking after your mates - but none of those are uniquely Australian however much some of seem to think they are.