Grand Designs : Season 4

Louise and Milko wanted to build the home of a lifetime. Milko's job as a well-paid City banker meant they could think big, so Louise set up her own architectural practice and they bought a disused violin factory in the heart of London's Waterloo. The crumbling building was hemmed in on all sides and had no views, but Louise had a vision of a spectacular loft-style home that would combine stunning design with utter luxury

David and Greta loved their home, a modernist structure in Surrey that they had built themselves almost 40 years ago. It was filled with things they'd chosen over the years – design classics, mementoes, David's paintings. But that house was falling apart and had to come down. Meanwhile, they had lost their hearts to a German post-and-beam house, designed by architect Peter Huf and available as a customised kit.

Kevin returns to see whether the couple's solo attempts to transform a wreck of an old stone building in Leith, with no previous building experience, has been successful.

David and Anjana's tiny coach house was proving too small for them and their two children. So they decided to build a new house in their own garden, which was big by London standards. But this particular grassy plot came with problems. It was overlooked by huge blocks of flats, and in the middle of it stood a chestnut tree they weren't allowed to cut down. They came up with an inspired solution: they would build a curving house along the borders of their plot. What's more, they would do a lot of

David and Anjana's tiny coach house was proving too small for them and their two children. So they decided to build a new house in their own garden, which was big by London standards. But this particular grassy plot came with problems. It was overlooked by huge blocks of flats, and in the middle of it stood a chestnut tree they weren't allowed to cut down. They came up with an inspired solution: they would build a curving house along the borders of their plot. What's more, they would do a lot of

When Reuben and April came across a ruined 19th-century house amid the tower blocks of Leith, Edinburgh, they saw it as their future home. They had no clear idea of how to restore it, and precious little building experience. Still, they were young and fit (they had met on Reuben's climbing wall) and they liked a challenge. So they bought the crumbling shell and set about transforming it with their own hands.

David and Greta loved their home, a modernist structure in Surrey that they had built themselves almost 40 years ago. It was filled with things they'd chosen over the years – design classics, mementoes, David's paintings. But that house was falling apart and had to come down. Meanwhile, they had lost their hearts to a German post-and-beam house, designed by architect Peter Huf and available as a customised kit.

Kevin returns to see whether the couple's solo attempts to transform a wreck of an old stone building in Leith, with no previous building experience, has been successful.

Louise and Milko wanted to build the home of a lifetime. Milko's job as a well-paid City banker meant they could think big, so Louise set up her own architectural practice and they bought a disused violin factory in the heart of London's Waterloo. The crumbling building was hemmed in on all sides and had no views, but Louise had a vision of a spectacular loft-style home that would combine stunning design with utter luxury

Anjana and David Devoy started building a contemporary home that curved around a protected chestnut tree in their garden. Kevin McCloud returns to see if their plan worked.

Kevin revisits David and Greta Iredale, who replaced their original house which they designed and built themselves with a German built, precision engineered Huf Haus.

Kevin revisits Tony and Jo, musicians with Scottish Opera, who had long dreamed of a home in the countryside. They found a perfect site on the Clyde estuary in Argyll and Bute. Located in a small village on a hillside, it had glorious views as far as the isle of Arran and was less than an hour's drive from Glasgow. Inspired by local oak-framed barns, they gave architect Andy McAvoy an open brief. In return, he gave them a design that fused medieval and modern and promised a beautifully simple in