By Mike Collett-White LONDON (Reuters) – With a range spanning the cardigan-clad sweetheart in the hit musical "Grease" and the leotarded gym instructor in the raunchy single "Physical", no one could accuse Olivia Newton-John of playing it safe in 40 years of singing country, pop and rock. The Australian, who was born in England and is touring there for the first time in 35 years, admits to being terrified at some of the choices she made in a career boasting four Grammy awards and a lead role in the biggest musical movie hit in U.S. history. …
