Seward told OK magazine: "I think in her heart Beatrice would like to be married in Italy where Edo's from, but there's no way the Queen will fly to Europe for the wedding so it will have to be in England."
She pointed out that Princess Beatrice of York is "more pliable" than sister Eugenie and will make it a priority to "keep everyone happy".
Seward was confident that the ceremony wouldn't be held at Westminster Abbey like the Duke and Duchess of Cambridge's wedding, it will more likely be at St George's Chapel in Windsor, the "family church".
Princess Beatrice will then have to face the reality it could be like a "re-run" of Princess Eugenie's nuptials, when she married long-term partner Jack Brooksbank last October.
News of the Princess' engagement to the father-of-one property tycoon, 34, was announced by her parents, The Duke and Duchess of York, on Thursday last week.
Mozzi comes from a family of Italian aristocrats and proposed to Beatrice on a trip to his native country, where they stayed in the luxurious cliffside village, Positano, on the Amalfi Coast.
Seward predicts the wedding will be "traditional with a modern twist" and Princess Beatrice will opt for a "simple" dress.
"Beatrice is used to being criticised for her fashion choices and I know she gets hurt by some of the unkind remarks," Seward shared with OK.
In regards to pageboys, Mozzi's two year old son Christopher "Wolfie" Woolf from his previous relationship would be the obvious choice.
READ MORE: Ex to Princess Beatrice's fiance opens up about new couple
Mozzi is the first single parent to join the Queen's family in the last century at least, making Beatrice the first royal in a long time to become a stepmother.
But Seward thinks the Queen won't be bothered that Princess Beatrice, ninth in line to the throne, is marrying someone who already has a child.
She continued to say that the Queen is a big fan of her granddaughter, and her thinking is "quite modern". Seward believes it would have worried her more when Prince Harry proposed to divorcee, Meghan Markle.
Beatrice and Edoardo The couple have had a whirlwind 11-month romance - from meeting, dating, moving in together and getting engaged within a year. However Mozzi has known the York princesses since they were children.
He suffered a great loss when his stepfather Christopher Shale died in 2011. Princess Beatrice was among the 700 mourners who attended the funeral.
In a statement, the couple said of their relationship: "We are extremely happy to be able to share the news of our recent engagement.
"We are both so excited to be embarking on this life adventure together and can't wait to actually be married.
"We share so many similar interests and values, and we know that this will stand us in great stead for the years ahead, full of love and happiness."
