Sarah, Duchess of York is reflecting on how wonderful it is to be looking after the late Queen’s corgis, Muick and Sandy, since the death of the monarch in September.

“They really make me laugh and they follow me around,” says Sarah, ex-wife of the Duke of York.

“Sometimes I break a little biccie – a digestive biscuit – in the same way the Queen broke it into little pieces, and give it to them and tell them to remember their boss.”

There’s a kookiness about the bubbly, gregarious duchess, or ‘Fergie’ as she is known to millions – a charity founder and philanthropist, one-time Weight Watchers spokesperson, prolific children’s author and now Mills & Boon romantic fiction writer – as she veers blithely from one subject to the next, oozing warmth and humour.

But there are conditions to this interview. No questions about her ex-husband, the Duke of York, please; only one about the Duke and Duchess of Sussex.

Sarah, 63, clearly doesn’t want to drop any clangers, given the raft of royal scandals she has sparked over the years – from being cast out from the Firm amid a toe-sucking scandal in the 1990s, to reportedly falling deeply into debt in those early years.

But she was invited to spend last Christmas with the royal family at Sandringham, so it seems relations have thawed. Meanwhile, she still lives in the same house as Andrew at Royal Lodge, Windsor, even though they’ve been divorced for more than 25 years.

Today, though, we are here to discuss A Most Intriguing Lady – her second historical romantic novel co-authored with Marguerite Kaye, who has written more than 50 Mills & Boon books.

It’s inspired by the duchess’s great-great aunt, Lady Mary Montagu Douglas Scott, who in the fictional tale is born into the highest society, fighting to define her place in life.

Indeed, there are similarities, Sarah, who is of aristocratic stock, agrees. Like her character, “I’m very steadfast and stoic,” she says. “I won’t let anyone down. I’m very loyal.”

Ever leaning towards the positive, she describes the mishaps she’s been linked with over the years as ‘enormous learning curves’. She says people don’t know the real Sarah, but she is strong and happy in herself.

“I’ve done the work to get to myself. I’ve done masses of mental therapy. I probably reached to the wrong places and the wrong people and made, as you call it, mistakes. I don’t call them mistakes. I call them enormous learning curves.”

Does that mean her setbacks have ultimately helped her grow to become a better person?

“I think the obstacles are the way, as opposed to in the way. I feel very strongly that I completely and utterly own my very naïve self and made endless different wrong decisions, whatever they may be, but in the end, it’s got me to today as an author. I’m a person in my own right, I’m Sarah,” she reflects.

Having given her own interview to Oprah Winfrey after her divorce in 1996, when she declared that royal life was ‘not a fairy tale’, what does she make of Harry and Meghan’s decision to move to the US and publicise their lives, both in their TV interview with Winfrey and Harry’s book, Spare?

“I divorced, went to America, wrote a book, went on Oprah and did 12 years as the longest running spokesperson of Weight Watchers. I looked to America to support me and to help me and I really can’t thank the American people enough for what they gave me and what they did for me.

“So I believe very strongly that I have absolutely no judgment on any other person’s life, and I look at how much she [Meghan] loves him [Harry] and loves the children and gives him a love that he’s never had before. That’s how I look at it.

“The most important thing is that the sun will come up tomorrow and the day will move on,” she continues. “The most important thing is, Diana would be so very proud of Archie and Lili. She would have adored every moment of it.”

The person she is happy to share recollections of is the late Queen. At the recent funeral of her friend Lisa Marie Presley, Sarah made a speech referencing her (former) mother-in-law – and today the memories come flooding back.

“I’m so lucky. All my life, I was lucky enough to know ‘The Boss’, HM. Like the nation and the world, she was always there. It was like having a hand at your back. It just made you always strive for being better and trying to be better, learning from her, whenever you were with her just taking everything she said as a memory. She was such an incredible legend for us all.”

She recalls in the final months before her death, she would send the Queen pictures of flowers and shrubs from her garden.

“For me, she was more a mother than my own mother. Aren’t I the luckiest person alive to have had that great honour? When I was with her, I used to say, ‘I can’t believe it. People wait and put on their best dress to have an audience with you, and I’m wandering around the garden in wellies!’”

She also has nothing but praise for the King.

“It’s incredible what he’s done for the environment. He was a trailblazer and many years ago, everybody said, ‘What’s he talking about?’ But he’s right. I’m a great believer and supporter of him, as I am of the Queen Consort.”

She is extremely close to her daughters, princesses Beatrice and Eugenie, and the fact she has always been there for them contrasts with her own childhood anchors.

After her parents divorced in 1974, the duchess’s mother Susan Barrantes left when Sarah was 13 to start a new life in Argentina with polo player Hector Barrantes. She was killed in a car crash in 1998, the year after the death of Diana, Princess of Wales.

“My daughters come first in my life, they always have. Because I lost my mum so early, I’m subconsciously very present with them. When I brought them up, I always left my problems at the door. Your problem is not their problem – it’s not their fault. We laugh together a lot. We are just very close.”

She says she sees a lot of them, as she does the grandchildren, Sienna and August (Princess Eugenie is also pregnant with her second child).

“I’m ‘Super Gran’,” she says, laughing. “When my grandchildren see me, they immediately laugh because they know I’m going to be up to something, up to no good somewhere.”

How has she been able to co-parent so successfully?

“By being grateful,” she suggests, vaguely. “Every time I think about about co-parenting and co-grandparenting and about divorce, marriage and all these different things, I still come back to the principle that the sun will come up tomorrow, and be grateful, just get on with it.”

Having penned romantic fiction, she admits she’s a sucker for romance, but dismisses any suggestion that, despite living in the same house, she may get back together with Andrew.

“Oh bless your heart,” she retorts, laughing. “No, I think we’re great as we are.”

Would she like to find love again?

“I think I’ve got too much baggage. I look at today and if suddenly I find love again, well, that’s another bonus, isn’t it?”

There have been reports that Andrew could be evicted from Royal Lodge due to cuts in funding, but Sarah remains vague about their future there.

“Honestly, I operate from living in the present. You never get complacent and it makes for a better day because you never get disappointed, then. You look at life and you go, we can adapt, we can be flexible.”

Her next novel will be centred on Victorian female detectives – she calls it ‘Sherlock Holmes meets Peaky Blinders’ – and there’s a TV series adaptation planned for both her published novels.

Meanwhile, there’s the Coronation coming up, although she says she doesn’t know if she’ll be attending.

“Never presume, never assume. I don’t know. But I’ll be there at the end of the drive with a cup of tea if I’m not there.”

A Most Intriguing Lady by Sarah Ferguson, Duchess of York, with Marguerite Kay is published by Mills & Boon, priced £14.99. Available March 30.