Grand Designs revisited: channel 4 show revealed behind-the-scenes look at Britain's first Passivhaus — here's what happened next

As Grand Designs celebrates 20 seasons on our screens, we've been catching up with the programme's participants, sharing their stories on whether their house really did turn out to be the home of their dreams.

From spiralling budgets to building site calamities, here's what some of the participants have been up to since the cameras stopped rolling.

Helen and Chris Seymour-Smith

This couple took a creative approach when they built on a plot of land with a barn in the Cotswolds. They hid their family home almost completely from view.

Helen, an architect, and Chris, an architectural designer, took a derelict 300-year-old stone barn and built a new house into the hillside beneath and behind it.

Deliberately unobtrusive, L-shaped Underhill House was ahead of its time, virtually heating free, the first certified Passivhaus in England. The barn was renovated as a base for Helen’s practice, Seymour-Smith Architects, bringing the build cost to £600,000.

The couple, who had previously lived in Kentish Town, bought the land from Helen’s father for a “token sum” in 2007 and moved in 2010 with their son, now aged 15. But they did not stay.

Two years after appearing on Grand Designs they sold the barn for £1.1 million - and surprisingly invested in a wing of a 16th-century manor house in the same village. Helen, now 45, is still slowly renovating that property and learning new building skills.

Helen and Chris separated in 2017. Helen made friends with the new owners of Underhill House, a couple of empty-nesters who had long nurtured ambitions of building their own grand design but never had the time.

“When I visit I don’t feel at all sad,” says Helen. “The process of designing and building it was amazing, very different from my usual loft conversions and side extensions in London.”

Since appearing on the show, she has become an expert on low-energy building. Her practice has amassed an impressive portfolio of contemporary, low-energy houses, often in sensitive rural locations.

VERDICT: the house did not sustain dramatic life changes.