Thank you, everyone, for your thoughts. Very helpful, although probably I won’t be tossing a coin! Apologies for the duplicate original post.
I have always been quite decisive in making life choices but this one is causing me difficulties!
I may have down-played my and my partner’s preparedness to live in AUS, even with the minuses. If we were to move, very much it would be because also we wished to do so, having weighed up all of the issues, and not only because a child had chosen likewise.
@Marisawright, thank you for your replies. In terms of fiscal and pensions advice, the firm I use is an international firm with bases in the UK and AUS and it has dual-qualified advisers with a track record in these areas. Your point about timing is particularly pertinent, which is one reason why I need to make a decision shortly!