When I tracked down Asthall Manor it was because it had been the home - and playground - of the teenage Mitford sisters (and brother). A private residence, it opens its gates once a year for a sculpture exhibition in the grounds. But what I discovered, when I went to visit, was that its owner was planning to open up "the barn" as a separate residence. "Barn" is what they call it, and what the Mitfords before them called it. But don't be misled. How many barns do you know that have a ballroom? This major extension to the manor house was built by David Mitford for his tricksy brood, who slept in the upstairs rooms and were inducted into high society in debutant balls downstairs. The ballroom is now available for hire for events, and the upstairs - a self contained flat which still has Nancy's drawings on the wall, and hand painted signs on the lintels bearing the children's nicknames - can be rented for holidays. It's too, too divine.