IT SEEMS that almost every week Sarah Ferguson - the Duchess of York, known to one and all as Fergie - makes headlines with her efforts to re-brand herself and explain her troubles. There are the weight-loss problems, the ongoing differences with the Royal Family and her financial difficulties. But how did it all start? It seemed like a fairy-tale come true when Sarah married the Queen's favourite son, Prince Andrew, and became one of the best-known women in the world. She was feted wherever she went - and she went everywhere. But the Duchess's world was to come crashing down in spectacular fashion. We all heard the rumours, now here's a book that sets out the facts about all the scandals. Finally, the explosive truth from two experts - CHRIS HUTCHINS, the writer who broke the palace-rocking story of Fergie's risqué liaison with handsome Texan Steve Wyatt, and PETER THOMPSON, a former editor of London's Daily Mirror, the paper that ran the sexy