Finding eight old cassettes hidden in a cupboard transported former model Jenny Boyd right back to the 1960s.

The sister of Pattie Boyd and former sister-in-law of both George Harrison and Eric Clapton, Jenny had conducted interviews with the greats of the rock world back in the late 80s/early 90s for a book which was originally published in 1992.

And decades later she has come across those interviews again – including George Harrison, Ringo Starr and Joni Mitchell – which form part of an updated version of the book, now titled Icons Of Rock.

“Hearing George brought back all of the memories,” says Jenny.

“You hear their voice and go straight back there.”

Jenny, now 75, was at the epicentre of the Swinging Sixties, even travelling to India with the Beatles to visit the controversial Maharishi Mahesh Yogi. In the 1970s she married drummer Mick Fleetwood, not once but twice.

Does she pinch herself that she was at so many pivotal moments in music history – from the creation of the Beatles’ White Album to being in the studio when Fleetwood Mac recorded the album Rumours?

“That was just how it was,” says Jenny, nonchalantly. “It was incredible really when you look back.

“That’s what a lot of people wish they had now. The spirit of it, living in the moment.”

Jenny had known George from when she was 16 years old.

In 1968 she was invited by the Beatles to Rishikesh along with Pattie, during the band’s “transcendental meditation” phase.

By then Pattie had been married to George for two years. “At the time I was a very shy 19-year-old,” says Jenny. “I found it so exciting.”

And regarding the Beatles’ songwriting, she said: “It’s almost as if they didn’t have to think about the songs. They were transmitters, they just picked it up.

“They would have their guitars, sitting on top of the bungalow – then came the song Bungalow Bill.

“All the songs they wrote were what was happening then. They were so in the moment.

“One song John Lennon got on the rooftop. He said, ‘I couldn’t sleep last night’, and that became I’m So Tired.”

One Beatle not in her book is Sir Paul McCartney, because his late wife Linda, a vegetarian and campaigner, turned her down.

“I did originally approach Paul,” says Jenny. “I spoke to Linda to see if I could interview him.

“She said, ‘Do you eat meat?’ I said, ‘I eat chicken’. She said, ‘Well chicken is meat, so no, he can’t’.

“I was almost tempted earlier this year to see if I could get hold of him, but it was a bit late. Somehow I’ll get a book to him…”

Between them Pattie and Jenny inspired some of the best love songs from the 60s and 70s.

In Pattie’s case George Harrison wrote Something for her while Eric Clapton wrote Layla and Wonderful Tonight. Sixties star Donovan wrote Jennifer Juniper for Jenny, although their relationship was more of a friendship. “We were just part of the music world,” says Jenny, who also had a stint as a dancer on 60s show Ready Steady Go. “It’s so odd. Pattie had two guitarists, I had two drummers.”

Jenny married Mick Fleetwood in 1970, divorced, then married him again in 1977, finally divorcing in 1978. She subsequently married drummer Ian Wallace from King Crimson in 1984 which lasted until 1990. Still good friends with 76-year-old Mick, she recalls being in the studio in 1976 when Fleetwood Mac were recording Rumours, which became one of the biggest-selling records in history.

“It was heartbreaking because Mick and I were breaking up at the time,” says Jenny. “Everybody was breaking up. You would go to the studio and listen to Stevie Nicks singing her song about Lindsey Buckingham or Christine McVie about John. Then you would go into one of the little sitting areas and there would be someone weeping. It was such an extraordinary time.

“I heard them rehearsing and I knew, absolutely beyond a shadow of a doubt, this was going to be big.

“It was to do with the harmonies. That’s what the Beatles were about too. Every song was amazing.”

Jenny and Pattie’s dad Colin, a pilot, was injured in the Second World War and badly traumatised. “I have vague recollections of this man just staring at walls,” says Jenny. “He didn’t communicate.”

She was determined her daughters Amy and Lucy would have a good relationship with their father.

Jenny now enjoys spending time writing, dividing her time between London and California, and regularly sees Pattie, 79, who is married to property developer Rod Weston.

“She’s great, doing very well.”

Before releasing the interviews in their entirety for Icons Of Rock, Jenny checked with Ringo, Eric and George’s widow Olivia.

“Olivia was absolutely fine with it,” says Jenny. “And with Eric I spoke to his manager. He’s so open about himself, so he was fine.

“I texted Ringo. He did a couple of tweaks. He didn’t want me to use his audio for the audiobook because he said ‘I don’t sound like that anymore’. It will be so nice to give a copy to him.”

• Icons of Rock by Dr Jenny Boyd (John Blake Publishing Ltd, £22). To order a copy for £22 visit expressbookshop.com or call 0203 176 3832. Free UK P&P on online orders over £25