Was it an exercise in self-promotion? A faux royal tour? An attempt to monetise their titles? Or a chance to highlight their charitable causes?

The reality is that the Duke and Duchess of Sussexes’ four-day visit to Australia was all of the above.

In this brave new world of California-based royalty, in which the couple mix lucrative business deals with charity work, this is the future.

The whirlwind tour that took in Melbourne, Canberra and Sydney was considered something of a test, a chance to see whether this version of royal life – the brand Sussex version – was sustainable.

The conclusion, much to the likely dismay of their many critics, is that, yes, it very much is.

The visit was considered a huge success and will now form a blueprint for future tours, including, potentially, those to the UK if they can get the security they want.

“We’ve tested the playbook, it worked,” a source close to the Sussexes told The Telegraph in Sydney shortly before they prepared to fly back home.

“They’re doing the right thing. Whether you want to call it half in, half out or – as they would probably describe it – just doing what they want to do and doing it in a really positive way, this week has given us reassurance that it is the right course of action. This could absolutely act as a blueprint for the future.”

It has been a fascinating exercise. Before the couple landed in Melbourne on Tuesday, the Australian media was largely indignant, asking what these non-working royals thought they were doing.

The tone of the coverage, however, shifted as it became clear that the Duke and Duchess were being welcomed at every engagement with open arms.

The disconnect between the negative commentary and the reaction on the ground is not lost on the couple.

The Duke is philosophical. “One thing that Harry often says is that the truth will always out,” said one member of his inner circle. “The more they do of this, the more that people see them, interact with them, the more they see that there isn’t an agenda here.”

The sticking point will always be the couple’s need to make money.

That clash between public duty and personal interests was drawn into sharp focus this week as high-profile visits focused on mental health, and military veterans were mixed with commercial opportunities.

As the Duke spoke to a live audience about the pressures of fatherhood, a shiny new website was launched positioning the Duchess as a fashion influencer. Every item of her tour wardrobe has since been swiftly added, alongside affiliate links from which she will take a cut of profits.

On Friday, after joining sick and injured military veterans on a boat trip around Sydney Harbour, the Duchess was interviewed on stage at a “girls’ weekend” retreat that cost £1,400 per ticket and saw her pocket a decent sum.

Aides insisted that the fee allowed the couple to break even, funding the cost of their nine-strong team to fly to Australia, their accommodation and security.

“This is how life is for 99.99 per cent of the world,” one source said. “They have got to work to make a living, they have to pay the electricity bill just like everyone else. They are not funded by the taxpayer.”

Team Sussex is acutely aware that the pre-tour criticism largely concerned the cost to the public purse.

“It’s important for them and for us as a team to make sure that these tours are not funded by the taxpayer, nor the charities they are trying to shine a light on, but through private means,” one aide said.

While there has been a small, largely observational, police presence at public-facing events, the Sussexes’ team said there was “no comparison” to the public cost of their previous visit to Australia in 2018.

Certainly, while large crowds have greeted the Duke and Duchess on most of their engagements, it was nothing like the circus that accompanies an official royal tour organised by the Government.

Whether or not the couple still managed to maintain the magic is subjective. On the ground, the thousands who have shaken hands with the couple this week, hugged them and discussed deeply personal issues such as mental health, bullying and domestic violence, believe they have.

The Australian fashion designers whose creations have been worn this week by the Duchess have been celebrating a significant spike in sales.

Julia McCarthy, the founder of small Melbourne label Friends with Frank, two of whose outfits have been worn by the Duchess, said it was a “special moment” that had prompted “amazing traffic” to the website, a new buzz on social media and a host of new customers. “The Meghan effect is very real,” she said.

Michael Hartung, the Invictus Australia chief executive, said the world was “a different place” during the couple’s visit in 2018.

“There was a bit of negativity surrounding their return visit and I think that’s all been put to rest really,” he said.

The Sussexes could have flown to Australia, been handsomely paid for various commercial deals and personal appearances, and flown home again. Their critics believe that’s exactly what they should have done.

This, however, was never going to happen.

“The work we do, we really enjoy it,” The Duke told an audience in Melbourne. “We get to hang out together, meet amazing people and go to some incredible places. And that service, that giving back, for me, has been a cure.”

Invictus, for example, gives him his “annual fix” of connecting with the military community and putting life into perspective.

The Duchess is said to have observed during their 2018 tour: “I can’t believe I’m not getting paid for this.” Well, now she is. The Duke is getting his fix and the crowds have welcomed them with affection.