It seems the address was OK even though our address has a letter after the number. My wife has the ANZ Black Amex which was declared on the form - as soon as we removed that it worked. Of course it does mean that the application is not completely correct now but if they question her she will just tell them to spend a bit of money improving their software. It is absolutely ridiculous that the form wouldn't submit yet wouldn't highlight what the problem is.
What mlob said was correct. Your ANZ Amex is bank issued and doesn't count as an 'amex' card in your application so your application was indeed correct.