Steve Mills, 55, worked as a cop in east London for 27 years, on the beat in Hackney and Newham.
But after retiring he upped sticks with wife Caroline, 55, and daughter Charlotte, 27, leaving Romford, Essex, for Scotland - where both Steve and his wife have family.
The couple started looking for a place to live on the west coast, but fate intervened when they ended up buying a home built by Steve's great-grandfather in 1901.
The red sandstone castle, Dunavertie, overlooks Wemyss Bay, Inverclyde, with nothing separating the garden from the sea.
Steve had never been inside the imposing building as a child, but grew up with his gran pointing it out on the way to visit family in Largs, North Ayrshire. Dunavertie was built by his great-grandfather, Charles McNeil, in 1901 after he became wealthy from designing manhole covers for ships.
It was initially built as a seaside home, but later became the main base for the family.
But in the 1940s it was sold, and in the Second World War was used as a spy base for MI6, as well as a home for evacuees, according to conflicting reports. In the post-war years it became a B'n'B, before being divided up into three flats.
The couple are now living in the ground floor flat, and believe that fate intervened in bringing Dunavertie back into the family.
Steve said: "It feels fortuitous, it just so happened that it was on the market when we were looking for somewhere on the coast. "You could call that fate or whatever - my wife thinks it's fate." ]
They bought the three-bed flat for £130,000 and spent nine months replacing the electrics, flooring and bathroom and kitchen. Steve added: "It was supposed to have been used as a base for spies in World War II.
"I think my mother and aunt spent weekends and holidays there. "I grew up with furniture form the inside of the house, but I'd never been inside." Steve's mother, Marianne, trained as a midwife in Glasgow before she moved to New Zealand in the 1960s and married a man she met there.
But in 1973 the marriage ended and she moved back to her mum's home in Stepps, North Lanarkshire, with Steve and his sister. Ten years later, Steve met Caroline, just before he joined the Royal Navy. After leaving the Navy, he joined the Met in 1987 as they were offering a relocation package - but he was thrilled to move back north of the border, although his son, Ben, 29, still lives in Oxfordshire.
The couple's daughter, Charlotte, lives nearby in Gourock, Inverclyde, and Steve said the entire family loves having parties in the huge flat. The dad-of-two said: "We started looking at prospective properties and Caroline's aunt spotted that Dunavertie was up for sale.
"I had always known about the house because my family lived in Largs.
"When I heard the name, my ears pricked up a bit.
"It was a bit run down and had lain empty for five years.
"We were bidding against somebody else, they got it and we were gutted.
"But six months later they pulled out.
"It was meant to be.
"It's part of our family history." The first and second floors still have the ornate decorations designed by Mr McNeil, including mosaic tiles and wooden panelling. The couple live in the former servant's quarters, and their front room would have been a schoolroom when Dunavertie was a family home rather than a holiday house. Steve said: "It was like the Hamptons of Scotland - wealthy people moved from Glasgow to the coast."
But the castle was also a dig at a local aristocrat, Lord Inverclyde, who was reluctant to give Mr McNeil land to build on as he was 'new money'. To annoy Lord Inverclyde, Mr McNeil designed Dunavertie to be a miniature version of Wemyss Castle, which has since been demolished. Legend has it that locals nicknamed Dunavertie 'Spite Castle' following the spat. Steve, who works as a groundsman in a holiday park, said:
"He built the house after the railway line opened in the 1860s.
"The story goes that he asked Lord Inverclyde for some land but only got a strip as he was 'new money'.
"So he built Dunavertie in the image of Lord Inverclyde's home, and the story was it was called 'Spite Castle' - because every time Inverclyde passed to go into the village he would see the castle."