With the allegations concerning the Duke of York's friendship with convicted paedophile Jeffrey Epstein hanging over the nuptials like a dark cloud, Princess Beatrice's wedding was never going to be an easy royal event to plan.
The small matter of how to cram all their nearest and dearest into the "cosy" 150-seat Chapel Royal was already proving difficult enough, but now Beatrice and her fiance Edoardo Mapelli Mozzi face an even bigger conundrum: How to solve a problem like Harry and Meghan?
With acrimony between the newly-exiled Sussexes and the Royal Family having seemingly reached fever pitch over the weekend following the couple's foot-stamping salvo over the loss of their "royal" status, naturally the bride and groom want to avoid any ill-feeling on May 29.
The Sussexes have been accused of "losing all sense of perspective" after making an extraordinary online swipe at the Queen and other royals in a sharply-worded "update" on their personal website.
In a surprise twist, the lengthy broadside appeared to single out Beatrice and her younger sister Eugenie by making the point that there was a precedent for "other titled members of the Royal Family to seek employment outside of the institution," while they were being subject to a 12-month review period as they seek financial independence in North America.
Eugenie works as a director at an art gallery while Beatrice has a role with a tech company start-up. Although they are both HRHs who occasionally carry out charitable engagements and accompany the Queen to royal events, unlike Harry and Meghan neither have publicly-funded bodyguards.
The thinly-veiled criticism of the cousins has shocked royal watchers – not least because Harry had previously been very close to the York sisters. As children they enjoyed skiing holidays together when their mothers Diana, the Princess of Wales and Sarah Ferguson, the Duchess of York were chummy during the Eighties and Nineties and this carefree relationship carried on throughout their teen years extending into early adulthood when they were all still finding their way.
Yet, this unexpected outburst suggests that the family rift between the Sussexes and the Windsors is now affecting cousinly bonds that were once so strong.
Although Beatrice and Edoardo's wedding invitations have not yet been sent out, there is no question that Harry and Meghan will be among the tight-knit guest list for the 'low-key' ceremony and reception being hosted by the Queen at Buckingham Palace.
Yet with tensions rising, a source close to the happy couple yesterday admitted that while all members of the family had been informed of the date in advance of the formal 'stiffies' being posted, there was still uncertainty over the Sussexes' RSVP.
"Of course Harry and Meghan will be invited but it is up to them whether or not they choose to attend."
"The trouble with Harry and Meghan is that they think they are bigger than the institution," said one friend of the Yorks. "It's such a shame things have turned out like this."
As with all family disputes, knotted internal politics are at play. If they choose to sidestep the big day, the Sussexes risk being accused of snubbing Beatrice and Edoardo and upsetting the 93-year-old monarch and the Duke of Edinburgh, 98, in the process.
Yet if they accept the invitation, their appearance back in Britain for what could be the first time since they cease to be full-time working royals on March 31, threatens to overshadow the proceedings risking turning the wedding into the 'Harry and Meghan show".
To complicate matters further, the Sussexes do have form when it comes to upsetting the House of York over matrimonial matters.
Eugenie was described as 'hurt' when Meghan announced her pregnancy to the rest of the Royal Family at her wedding reception - before making the news public the day after the ceremony at St George's Chapel, Windsor Castle in October 2018.
The bride and her new husband Jack Brooksbank, were also said to be 'put out' when Harry turned up alone at the black-tie evening reception at Royal Lodge reserved for closest friends and family, and then only stayed for one drink.
Although the newlyweds appreciated that the Sussexes were flying out to Australia early the following morning for a royal tour, as one pal put it: " It's fair to say the relationship is not what it was."
The bond between all the royal cousins, but particularly Harry and Eugenie had always been strong. Eugenie was once described as sharing a "mischievous streak" with her "partner in crime" Harry - both having reputations in the family for their cheeky sense of humour and propensity to giggle during stuffy state occasions. As well as sharing in the trials and tribulations of living life in the royal spotlight, Beatrice, 31, and Eugenie, 29 are also closer in age to Harry, 35 than they are to William 38, and have long moved in the same social circles.
It was Eugenie who introduced Harry to Cressida Bonas, his girlfriend before Meghan who he dated for two years from 2012 to 2014. "Cuz" or "Eug" as she is affectionately known to Harry, was also rumoured to be among those who helped him get together with Meghan through mutual friends such as the stylist Misha Nonoo, whose Rome wedding both Beatrice and Eugenie attended along with Harry and Meghan last September.
Eugenie and Jack even stayed with the Sussexes at Meghan's Toronto home to celebrate Halloween in 2016 and for a while the couples were neighbours at Kensington Palace – Eugenie and Jack living in Ivy Cottage, while Harry and Meghan were a few doors down at Nottingham Cottage.
Yet there have been simmering tensions between the Sussexes and the Yorks ever since Harry and Meghan chose not to invite Sarah, the Duchess of York, to the evening reception of their own Windsor wedding in May 2018. (She wasn't on the guest list for William and Kate's 2011 wedding either, a snub which she later said was "hard" because: "I wanted to be there with my girls")
Fergie's exclusion from Harry and Meghan's Frogmore House bash came amid hurtful rumours that her nephew secretly suspected that she had been responsible for leaking the story of his relationship with the American actress back in October 2016 - a claim she strenuously denies.
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Sarah later hinted that it was the Queen who insisted that she at least be invited to the ceremony at St George's Chapel, Windsor Castle, saying: "She leads by such example and to include me is a wonderful gesture," before adding, diplomatically: "I felt honoured and grateful for Harry and Meghan to invite me... It was very kind of them and I think I can't thank them enough for doing that because it was nerve-wracking but I knew I was ready."
Yet some of the goodwill was undone when sources close to the former Suits star suggested that she was "horrified" by Andrew's car crash Newsnight interview last November.
Meghan was said to be particularly put out by the Duke's description of sex as a "positive act" for men in the BBC interview with Emily Maitlis about his role in the Epstein scandal. Having worked with the United Nations Entity for Gender Equality and the Empowerment of Women as an Advocate, it's fair to say the sorry saga has not sat well with Meghan's feminist credentials.
The Yorks, meanwhile, insist that Andrew is innocent until proven guilty and should at the very least be able to count on his family's support.
Behind the scenes, the Sussexes' shock decision to step down as senior royals and make a new life across the pond has also affected Harry's relationship with other cousins like Peter Phillips and Zara Tindall, to whom he is also close (although being just a year apart in age, Zara is friendlier with William).
Quite what the cousins make of the Sussexes' statement also appearing to take a swipe at their mother the Princess Royal remains to be seen. Following reports Anne, renowned as one of the hardest-working royals, is set to take over Harry's role as Captain General of the Royal Marines, their markedly pointed missive hit back: "The Duke's official military appointments will not be used as they are in the gift of the Sovereign. No new appointments will be made to fill these roles before the 12-month review of the new arrangements is completed."
Summing up the mood, a source close to Zara last night told the Daily Telegraph: "The overwhelming feeling is just one of sadness. She is incredibly fond of Harry and just feels so sad about what has happened. That's how they all feel."