This sequel to the minor 2005 hit based on Christiana Brand’s kid-lit series -- about a Mary Poppins-like nanny who looks a bit like one of Macbeth’s witches -- is mildly charming and passably entertaining. But instead of taking place in Victorian England like the previous movie, the action here picks up in World War II-era Blighty, where the title character (again played by the redoubtable Emma Thompson, who also penned the screenplay) goes to work for the stressed-out Isabel (Maggie Gyllenhaal with a British accent as counterfeit as her bogus southern twang in Crazy Heart), whose husband (Ewan McGregor) is off fighting the war. McPhee’s charges include her employer’s three rambunctious tykes and two miscreant houseguests (scene stealers Eros Vlahos and Rosie Taylor-Ritson as Isabel’s horrid nephew and niece). Once again, the crone-like nanny transforms into, well, the perfectly lovely Thompson after teaching her unruly brood five invaluable life lessons. Harry Potter devotees will get a kick out of cameos by Maggie Smith and Ralph Fiennes, while Babe fans will dig the menagerie of hyperactive CGI animals who, even without the distracting supplement of 3-D, still manage to do the darndest things. The most surprising thing about this otherwise fairly predictable romp is that it was directed by Susanna White, who helmed HBO’s superb 2008 Iraq War miniseries Generation Kill.