Hi, we are moving back, and I'm technically Australian too! If you can choose to be an Aussie (which most of you have done for at least a while), then you can certainly choose to move to the UK and consider yourself English. I've lived in both countries, throughout my 20's and early 30's in the UK and 15 years in Aus. My wife is English and we both miss many things, seasons, sophisticated culture, old friends, big family... and we get to go back and live in the UK and see it "afresh", nothing like leaving somewhere to have a fresh appreciation for it. We'll be living in the Home Counties in time for the school year to start in September.
It's worth going back a lot (!) before you make the decision though. Both countries are wonderful, but people make the mistake of moving from great areas here to frankly difficult areas there - friends of mine are constantly comparing the Manly to Manchester. That's like comparing Kensington to Sunderland... just too different.
Here's what I love about the UK (the list is equally long for Australia too!): the endless meg-city nature of London right in the centre of the world, country walks, long grass without snakes and spiders, weekends in Paris, endless places to visit within a few hours, history history history, market towns, farm produce, TV, real seasons, a 6 week lead-up to Christmas, fireworks on guy Fawkes night and old friends and family who knew you when you were too young to be pretending to be anything other than who you are deep down...
Good luck with your decisions and remember, you can always come back. But don't underestimate just how expensive the whole endeavour is!