Everyone loves a good Grand Design - something that has helped to make it one of the most popular property shows on TV. Yet after pouring everything into designing and building their perfect homes, some owners have decided to move on, with three Grand Designs currently on the market. The owners of a seven-bedroom castle in Yorkshire (left), left the owners 'exhausted and scarily remortgaged up to the hilt', according to the show's presenter Kevin McCloud (inset). The purchase and redesign cost around £900,000 and the house is on sale for £1,650,000. A four-bedroom 'doughnut-shaped' property in Milton Keynes (top right), which was built in a couple's back garden for £400,000, is currently on the market for £1million. The couple behind the build, Peter Berkin and his wife Chard, were at odds at the end of the project. 'Peter is going to be happy here,' said Mrs Berkin, before adding: 'It has been positive because I am still here with him.' Meanwhile a six-bedroom house in Newport (bottom right) is on sale for £1,795,000 with the owners refusing to be drawn on how much they had spent on the build.