The details of Meghan Markle and Prince Harry’s final lap of honour in the UK have been announced and the Sussexes have a full calendar until March 31, when they will be officially out of a job.

Among the engagements in the duke and duchess’ diary: a recording session with Jon Bon Jovi, church with the extended family, a music festival and a museum opening with Lewis Hamilton.

Two of the four engagements involve Harry hobnobbing with celebrities, which may be a signal of the showbizzy vibe the couple plans to cultivate when they’re just working schmoes trying to make a buck.

Much has been made of their desire for “financial independence” to bankroll a life in North America with son Archie, 9 months, and the alleged setback this week with the Queen “banning” them from using the term Sussex Royal in their future business lives.

Some commentators pounced on the monarch’s ruling as a disaster for Harry and Meghan, who have built a powerful brand with their Sussex Royal Instagram account and new website.

Others pointed out that all the couple may have to do is a quick judicious edit of their social media names and announce it to their 11.2 million followers. Whatever the truth, the issue brought into play another question around royals and money, namely which Windsors get to make it and why.

Even as Harry and Meghan were creating uproar in January with their unprecedented dream of exiting stage left to hang out their shingle,  a “brutally awkward” Chinese milk commercial starring the Queen’s eldest grandson, Peter Phillips, surfaced.

In it, Peter – newly single since his split from Canadian wife Autumn Phillips was announced – is presented with a bottle of milk on a silver tray carried by a butler.

Glass half full? Peter Phillips flogs milk. Photo: YouTube

Wearing a three piece suit and gold cravat, he chugs the milk from a tumbler and stares out a window, presumably at all he owns, “This is what I drink,” Peter intones.

Howling at Peter’s use of his royal status to flog a dairy product (in 2008, he sold his own wedding to Hello! magazine), the British media unearthed a different Chinese milk ad with Harry’s cousin, Kitty Spencer, as its leading lady.

It showed her saying a morning milk is part of the daily routine of any royal.

The cashing in by minor royals is “a wholly unedifying sight, a horrible little stain on the fabric of the nation,” wrote the Daily Mail’s Jan Moir. The Sun kept their disdain short and to the point: “Milking it.”

It’s nothing new for royals or those on the Windsor fringes to be entrepreneurial. Future king Prince Charles sells everything from organic chocolate and orange shortbreads ($11.50) to Prince of Wales check ladies’ gilets ($387) at his Highgrove farm shop, although all profits go to charities.

Sarah Ferguson, whose Instagram post this week for her ex-husband Prince Andrew’s 60th birthday divided her 257k followers, spruiked for Weight Watchers International in 1997. That gig meant she told the world her private pantry downfalls: “I drowned my sorrows in mayonnaise, sausage rolls and sandwiches from M&S.”

Fergie doubled down in 2015, appearing on a TV informercial for food blenders.

Zara Tindall, Peter Phillips’s sister, has had deals with Rolex and a pram company, and is the face of the Gold Coast’s annual Magic Millions horse racing event.

So, why can the Queen’s grandchildren and Princess Diana’s niece sell their connections to the highest bidder?

“If you are a working royal, then you don’t get to embark on commercial deals because there’s just simply too much of a conflict,” said Vanity Fair’s royals correspondent Katie Nicholl.

A working royal is one who does engagements on behalf of the Queen and the family and has an HRH title.

Still, while Peter and Kitty are entitled to promote Chinese milk, “It just feels tacky, and it feels like a conflict of interest, and it feels very much like they are cashing in on their royal connections,” Nicholl said.

Harry and Meghan aren’t likely to be so vulgar in their business choices.

“[He] is still a Prince of England and she is still the Duchess of Sussex,” Nicholl said.

“They will be acutely aware and will be treading very cautiously ahead of and around signing any deals.”