In an opulent room at the back of Buckingham Palace, in the face of determined questioning from the country's assembled tea-sipping, biscuit-nibbling royal correspondents, he respectfully insisted: no, he would not reveal the precise location in Britain of Markle's beagle, Guy.

"I'm protecting the privacy of a beagle, now," he commented. It was a hint that he was just a little surprised at where life had led him.

Knauf is 33 - the same age as Prince Harry - and was poached by the royals from the Royal Bank of Scotland, where he had crisis-managed a scandal over the chief executive's share bonus. Before that he worked at Treasury, and before that he wrote speeches and managed press for New Zealand's deputy PM and advised Helen Clark. He has a masters degree in science, politics and communication.

And here he was. Could he or could he not confirm that there would be peonies in the flowers at Meghan and Harry's wedding?

"I am very much looking forward to having lots of conversations about flowers," Knauf replied.

"I presume you think it's a joke," said the slightly miffed reporter.

"No, it's not a joke, I have been doing a lot of research," Knauf smoothly retorted. "I understand I will be talking a lot about flowers, I am very much looking forward to talking about flowers, today I have nothing to say about flowers."

To look at the tabloids, you'd think that royal weddings are almost the point of the whole institution. But beyond whether or not Knauf is truly looking forward to talking about flowers, his job at Kensington Palace is a lot bigger than bouquets.

He is in charge of the young royals' brand at a key moment in the evolution of 'The Firm', as Prince Philip has long referred to the British royal family.

Harry, at last, is all grown up. Gone are the days of nude billiards and fancy dress Nazi uniform. He has a fiancee and they are talking about having a family.

Once the whirlwind of the wedding dies down, Markle will become the fourth patron of the Royal Foundation of the Duke and Duchess of Cambridge and Prince Harry, the main vehicle for their philanthropic activities and - as such - the key expression of the next generation of royals, defining and channelling their beliefs, causes and character.

For the last decade, the kids have gradually become the grownups. The Firm now has three generations in full-time employment, with the oldest perceptibly making way for the youngest. And a married, settled Harry is the last piece of the puzzle.

This week Prince William was with the Queen as she received German President Frank-Walter Steinmeier at Buckingham Palace for lunch.

No explanation was given, but the intent was obvious. With post-election Germany at a delicate political moment, and the president walking a careful constitutional tightrope as he pushes parties towards coalition, it was the perfect teaching moment for a head-of-state-in-training.

William then visited Finland, marking the country's 100th anniversary of independence and delivering Prince George's Christmas list to Santa. It was another of the royals' so-called "Brexit diplomacy" visits, aimed at strengthening European ties even as the country leaves the European Union.

Meanwhile, Harry and Markle were due Friday to make their first official visit together - to Nottingham, where the Foundation's Full Effect program has been trying to divert young people from youth violence and crime. And on Monday Harry will attend the London Fire Brigade Carol Service at the end of the year that saw the Grenfell Tower fire, a significant and responsible gesture.

"[Harry and Meghan's] wedding effectively completes a chapter," says Robert Hardman, the Daily Mail's royal correspondent. "William and Harry will be the standard bearers for the monarchy for a generation, and now they're both sort of settled. You can really look ahead to the next chapter."

The monarchy has constantly adapted, incrementally and gradually, ever since Hardman took on this beat 25 years ago, he says.

"They just operate on a different timescale," he says. There aren't relaunches, new slogans or new campaigns. Even big changes aren't rushed.

A few years ago the Queen let it be known she wouldn't do any more long-haul flights, so the Prince of Wales stepped up for the Commonwealth meeting in Sri Lanka in 2013. The next two CHOGM meetings, however, in Malta in 2015 and in Britain next year, were inside the Queen's travel zone.

Earlier this year, the Duke of Edinburgh announced he was stepping down from royal duties aged 96. But he has popped up at several official occasions since, most recently the Remembrance Sunday service at Whitehall.

Hardman warns against assuming there's a grand plan for passing responsibilities down the generations. It's just a gradual, organic process, he says.

"We've now got the longest-lived monarch ever, the longest-serving heir to the throne ever, the longest royal marriage ever, we're in uncharted territory."

Opinions differ among royal watchers as to how the balance of power is moving between the palaces.

In August the BBC's royal correspondent Peter Hunt described a "bloodless coup". The departure of the Queen's dedicated senior official, Sir Christopher Geidt, Hunt said, "has meant her eldest son can exert more control over the monarchy's direction of travel".

"The heir who's waited and waited is more content and less anguished," he said. "With each year that passes his mother will do less and he will do more."

The Times reported there was a 'Project 70' at Clarence House, referring to Charles' 70th birthday in November next year and aimed at bolstering his image. His team are said to want to take over significant duties - for example, the running of the royal estates, including Sandringham and Balmoral (which grows blackcurrants for Ribena - expect them to go organic in the near future).

There are few duties that absolutely have to be performed by the monarch - most can be delegated, and many are already.

There is no reason, for example, Charles couldn't read the Queen's Speech in parliament, or take the salute at the Trooping the Colour.

About the only off-limits areas would be the weekly meetings with the PM and the formal appointment of archbishops and bishops, according to constitutional expert Bob Morris of University College London.

In August the Sunday Times printed a much-derided theory on its front page claiming the Queen was considering using the 1937 Regency Act to hand power to her eldest son in four years' time.

The Act is supposed to be used only if the monarch is mentally or physically incapable of performing her duties - for it to be a planned event would amount to a de facto abdication.

Palace officials pointed sceptics to the Queen's vow on her 21st birthday: "I declare ??? that my whole life, whether it be long or short, shall be devoted to your service."

Even through a weeks-long heavy cold this year, she was said to have read her red boxes of government papers every day.

But in May, when Prince Philip's retirement was announced, the Queen's private secretary reportedly told royal staff to expect her family would be doing more in direct support of the monarchy rather than individual activity.

And the princes have been much, much more visible this year - not just because of the 20th anniversary of their mother's death.

William quit his job as an air ambulance helicopter pilot to take up full-time royal duties in support of the Queen. He and Kate were to step up their share of royal engagements, and they moved back to Kensington Palace in London with their two (soon to be three) children.

Harry, too, is to be based there, in Nottingham Cottage on the palace grounds.

Hardman says it is a relief for Charles that his boys have "turned out well" and are working as a team.

"They were so much in the public eye, they put up with a hell of a lot and they've come through amazingly level-headed," he says. "They clearly get on with each other."

And Harry's emergence as a mature royal has been spectacularly successful.

"Just look at the Invictus Games, that's a pretty extraordinary achievement for anybody, let alone a young man to pull together.

"All they way through his military career there was this restlessness [to Harry]. He's certainly not someone who wants to just have a playboy lifestyle, he wants to get on and do things.

"Like his father actually. A lot of the previous princes of Wales were pretty useless. This one has created the biggest charitable network in Britain, and stays up to one in the morning writing memos."

Markle, a World Vision ambassador for the past two years (she will start at the Foundation with a clean slate), is going to fit in well.

She brings a familiar glamour to the royal family - Diana's legacy is written and read into almost everything the princes do. The first public outing of Harry and Markle, on Friday, was in support of AIDS charities. The princess of hearts has passed her enduring, untarnishable popularity on to her sons, and they wield it with ruthless skill.

As they continue to grow into their jobs, they will be an ever more crucial part of the royal firm.