3. The Newport Folly, Newport

Sarah and Dean Berry grew up on a council estate in Newport. Having moved away to London and made good, they have now returned home 17 years later and bought an 18th century folly - a castle perched on a hilltop. They not only plan to restore the folly to its former glory, but wrap a large modern extension around the original structure, with lots of glass to capitalise on the amazing views.