Fancy a cruise with a difference in 2015? then why not join Fred. Olsen Cruise Lines, Boudicca, for the ‘Poison, Murder & Mystery’ cruise, departing from Rosyth on 10 July 2015,  linking the Duchess of Northumberland’s ‘Poison Gardens’ at Alnwick Castle – which starred as ‘Hogwarts School of Witchcraft & Wizardry’ in the Harry Potter…