By Lucretia Munro Antiques Roadshow expert Will Farmer recalled the shocking moment a guest found out he had been duped into believing he had bought a collectable item – only to find out it was a fake. The guest was so taken aback from Will’s devastating news, he stormed of taking the glass bottle with him. Viewers have seen week after week, Will change people’s lives when he tells them an item they’ve had in the family for years, was worth an astonishing amount of money. But on that occasion, is one of the downside to the popular long-running BBC show. In a recent interview, he recalled: “A g…