When inviting a bear from darkest Peru into your terraced London house, the first thing to do is increase the coverage on your homeowners’ insurance policy. “Yes, a bear . . . about three foot six,” says Mr. Brown to the insurance agent on the phone in an early scene in Paddington: The Movie. The tenderness of Mr. Brown’s misguided specificity — it wouldn’t seem that the bear’s height is the most salient of details — endures as a mood in this film about an ursine immigrant to the U.K. who does, indeed, cause several thousand pounds’ worth of property damage. He overflows the…