Ah, yes - I had forgotten about RoundAbout Travel. My brother used them several years ago for the Finnair 'mini DONEx'and said that they were very good.
RoundAbout Travel is Australia's only round the world travel and multi-stop specialist. Speak to our experts to book you the best round the world tickets or multi-stop trip on quality airlines.
roundabouttravel.com.au
I disagree with
@justinbrett about DONEx's being very complex. Certainly OneWorld Award itineraries are highly complex because it involves snaring a string of award flights, but a revenue DONEx is an entirely different beast. All that it needs is D bucket availability, which is usually readily available if booking well ahead.
Of course, you could always book an AONEx and go F - but you then need to choose airlines and birds that have an F cabin to maximise that...
It's easy enough to do yourself, but a knowlegeable TA can save substantial $$ by booking through one of the other OneWorld airlines, rather than QF. As a customer based in Australia, doing it yourself would automatically funnel you through QF.