LOVED by hippies and Hollywood stars alike, Birkenstock sandals are now at the centre of a multi-billion-dollar battle between the firm's heir and his wife.At stake is the name of the company which sells 40,000 pairs of the no-nonsense shoes every day of the year. Fans include Leonardo DiCaprio, Gwyneth Paltrow and Johnny Depp. Susanne Papenbrock, 34, is divorcing the firm's heir, Christian Birkenstock, after a 15-year marriage and wants to take the company name with her. Newspapers have dubbed the divorce fight "Dallas on the Rhine". Ms Papenbrock, who walked out of the River Rhine castle she shared with...