I just learned of these films from a couple of interviews Naomie Harris did last year. They both seem to have bypassed American theaters, sadly, although both films look really terrific. She plays Ian Dury's girlfriend Denise Roudette in Sex & Drugs & Rock & Roll and a teacher in Kenya in The First Grader.
Sex & Drugs & Rock & Roll is available on DVD in the US now - Amazon.com: Sex & Drugs & Rock & Roll: Andy Serkis, Naomie Harris, Ray Winstone, Olivia Williams, Toby Jones, Mat Whitecross: Movies & TV
The First Grader is not yet available on DVD in the US.