COLD PLAY: A freshly cropped Renée Zellweger was in London over the weekend, taking a break from filming Anthony Minghella’s “Cold Mountain” in the cold mountains of Transylvania. She spent Saturday shopping at Nicole Farhi buying wooly layers for Romania but skipped Manolo Blahnik on purpose. “I don’t think those heels would do me very much good up the side of a mountain in Transylvania,” she reasoned. On Saturday night, Zellweger dined at Nobu with a girlfriend, and managed to slip in and out of the packed eatery without any fuss. As for her part in the sequel to “Bridget Jones’s Diary,” Zellweger said her plans are still up in the air.