LONDON.- This autumn Sotheby’s will hold a once-in-a-lifetime sale at the most magnificent of all England’s stately homes – Chatsworth, in Derbyshire. Chatsworth: The Attic Sale – a three-day auction – will have in it all the ingredients of the quintessential attic sale: an Aladdin’s cave of items at all price levels (estimates range from £20 to £200,000), each one with its own story to tell. More than that, though, the sale will have at its core a wealth of fine, rare architectural fixtures and fittings, the existence of which had been obscured by time. Discovered beneath layers of dust, these magnificent pieces – handsomely carved fireplaces, architraves, doors and shutters – were once part of the fabric of the many great houses that have featured in the Devonshire family’s extraordinary history, including Chatsworth itself, Chiswick House, Hardwick Hall, Lismore Castle, Compton Place, Bolto