After 13 years in a Victorian villa in North London, Sarah Wyndham Lewis and her husband Dale Gibson felt it was time for a change. But rather than heading off with their two teenage sons, Alexander and Matthew, to a cottage in the country, they moved further into town, to Southwark. "We didn't know the area well, but we love it now. It has a great sense of community, and the boys quickly came round to the move when they realised they were within walking distance of some good clubs and music venues." It wasn't just their location that the family changed; it was their whole style of living. The new home is a converted Dutch-style warehouse on four floors. "It isn't a mum, dad and two children sort of house; it is for four adults, where each of us can do our own thing," says Sarah. "The boys have independent access to their rooms and there are sitting areas on three floors so that we can have friends round, watch TV or chat without getting on top of each other." To achieve this, a new staircase was added at the back of the building, so that Matthew could have direct entrance to his room, rather than having to go through his parents' dressing room. The original staircase remains, turning up past the narrow book-filled landing and double doors of Dale and Sarah's bedroom to the top floor with its open-plan kitchen and living room.

The living area, at the street side of the building, is furnished with two made-to-measure leather sofas, and on the dark wood floor there is a decorative ethnic mat by Felt. Beside a distressed painted wood dresser is a tan leather Borg Mogensen chair. "Because the space and shape of this house is so different, we had to get rid of a lot of furniture, but in return I was able to buy some 'new' second-hand or antique pieces," says Sarah.

One of her proudest buys was a brilliant-red chandelier, bought on eBay, that hangs over the oval dining table in the wedge-shaped room at the back of this floor, while on the back wall is another internet find, a panel of black and white domes by Verner Panton.

The final surprise in this part of the house is the cloakroom. Hidden behind a simple black door, it is decorated with shocking-pink wallpaper. "Friends call it the 'Oh, Blimey!' room, because that's what people say when they first go in there," says Sarah.

The narrow passageway between the sitting and dining areas forms the galley kitchen, with Neil Lerner units and a Zodiaq worktop. A wenge wood floor by Listone Giordano gives a visual flow through the three spaces, and a final flight of stairs leads up to the roof terrace with its panoramic views across London.

Perhaps the most surprising outcome of the move, however, was what happened to Lil, the family's flatcoated retriever: she went from being just the family mutt to a model and style icon. "I used to walk Lil on Hampstead Heath, and I met a fellow dog-lover, Elaine, with her Collie cross Holly. We got talking about the lack of well-designed dog-collars, and so started designing them for ourselves and for friends. Then, two years ago, we launched our own website. When I moved to this house the ground floor, which opens off the street, was a bit of an un-specified space, so we decided to turn it into an office and showroom and give the company its own shop front.

Holly & Lil Collar Couture produces hand-stitched collars made with tweed, tartan and Chinese silk, customised charms and bespoke lines. And not all inquiries have been from pet owners: the collars have become fashion accessories in their own right. It seems moving house has opened up a new world for everyone in the family.

Holly and Lil's showroom is open Thursday to Saturday, or by appointment (07836 592415; www.hollyandlil.co.uk)

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