If you've decided you definitely want to spend your later years in the UK, then I think the 10-year plan is risky. Early adulthood - especially uni/college - is when most people forge the friendships that last into adulthood. They might even meet their future wife/husband. So if you wait till after uni, your kids are going to be more firmly anchored in Australia than they are now, so there's a good chance they won't want to return with you.
Of course, if you go now, there's no guarantee they won't move back to Australia as adults anyway. However, because they've had a chance to make friendships and feel settled, they will feel the attraction of both countries so there's a better chance they would stick around.
Amber is also right about pensions etc. If you leave Australia before the age of 65, you'll forfeit all rights to the Australian aged pension - and because your NI contributions are too low, you may not get much British pension. If you've got a healthy bank balance and good superannuation, that may be irrelevant, but worth being aware of.
If you do want the British pension, then enquire now about making Class 2 contributions while you are working in Australia. They are changing the rules early next year so it's important to sort it out now