For the first five years of her life, Delia Despair was brought up by a woman her mother happened to meet on Hove beach. “I'm going to Nigeria next week to rejoin my husband,” her upper class mother mentioned to the woman, whose name was Joan Priestley, “but I've got a baby of six months and I don't know what to do with her.”

“I'll look after her for you,” said Joan, and that was how Delia and her five-year-old sister Badger came to live in a house in Grand Avenue, Hove, with strangers.

It was an extraordinary beginning to an extraordinary life, a life now documented in her memoir The Grown-Ups Wouldn't Like It: Adventures in several countries and many languages, which is published on August 1. Delia Despair is not the author's real name, which remains a secret, but is the name of her blog (despairingdelia.com), where she writes funny accounts of her current life, as an older woman living in Hove.

Her memoir, however, is very different. Written in the same amusing and witty style, it details an unconventional childhood as the daughter of a globe-trotting diplomat, her experiences at a string of convents and smart schools including Roedean, and a series of jobs that veered from junior journalist at the Daily Telegraph to a tyrannical millionaire boss and to an encounter with terrorists in war-torn Cyprus.

Delia also recounts her happy marriage to a police sergeant from Lancashire, a man dismissed by her family as beneath her, forcing her to choose between him and them, and her encounters with famous names including the playwright Noel Coward, actor John Gielgud and the television cook Fanny Cradock.

The book begins with the account of how her mother came to hand her over as a baby to a complete stranger. “The thing is, the beach back then was full of middle class people and everyone knew each other,” says Delia. “It sounds extraordinary to do that, but I was very young and didn't really know what was happening. Badger and I went to live in Airlie House in Grand Avenue with Joan, her son Bretton and her mother. I had various 'mummies': my mother became my Blue Mummy because I think she must have worn a lot of navy, Joan was my Red Mummy, and there was also a Green Mummy and a White Mummy, who were probably visiting friends of Joan. “I was a bit confused about who my mother was as I saw so little of her, and she didn't come home until I was three. But I wasn't angry – I just accepted it all. In fact, I felt more angry with my father. I did not like him at all.

He tried to make me sit on his knee and I didn't want to, and Badger didn't want me to either. He was disinterested in children but he was very good at his job and he was devoted to it.”

One of the anecdotes in her book recounts Delia's experience as a 20-year-old au pair to the wife of a millionaire in Jamaica. “She was a monstrous woman, intolerable,” recalls Delia, who would later achieve fame with her book How To Get On With The Boss. “She treated the servants as slaves and reduced the Indian butler to a wreck. I felt obliged to stay for the five-month tenure that had been arranged, as she was a friend of a friend, but on the ship on the way back, she locked me in my cabin for the final three days and everyone on the ship was outraged with her.”

It was during her stay in Jamaica that she attended a glamourous party at a house called Cape Clear and encountered Noel Coward and John Gielgud. “I didn't like Gielgud, a cold man,” says Delia. “He was disdainful towards women. But Noel Coward was wonderful, laughing about the frightful people who sucked up to him.”

Delia's romantic life was fraught with both adventure in a series of exotic locations and with difficulties, especially when dealing with her father. On one romantic encounter, she writes: “When I wrote and told my parents all about everything – well, not quite everything – I received a great long lecture from my father. 'I'm not quite sure I like the sound of all these long walks you are taking, not do I like to think of you going into the bedrooms of young men,' he wrote. 'Young men are very hot-blooded and one thing can lead to another.' If only they would, I thought. I was longing to be seduced either by Bertil or by Ion, I didn't really mind which...”

The Grown-Ups Wouldn't Like It by Delia Despair, published on August 1 by Memoirs Publishing, priced £12.99.

Available from memoirs publishing.com, Waterstones, WH Smith, Amazon, Barnes and Nobel, and Google Books. Also available as an ebook.