More than one critic - myself included - reached for the superlative "a star is born" when describing the West End debut of Jac Yarrow in the title role of Joseph and the Amazing Technicolor Dreamcoat: "He received a spontaneous standing ovation on the first night at the end of his rendition of "Close Every Door"; but this is a performance that will open every door to him from here on in."Opening night was just four days ago when I met him backstage at the London Palladium, London's premiere...