Orla McAlinden Kildare, Ireland   Carleton House Carleton House, in Portadown, in the heart of Northern Ireland, was built as the townhouse dwelling of George Montagu, Viscount Mandeville, sixth Duke of Manchester. It is an imposing, three-story Georgian building on the Armagh Road, opposite a long stretch of terraced red-brick housing unimaginatively called Carleton Street.…