LONDONPeter Mullan and Jane Horrocks will head the cast of sophomore helmer Dexter Fletcher’s “Sunshine on Leith.” The Scotland-set musical, from DNA and Black Camel Pictures, is lensing for six weeks in and around Edinburgh and Glasgow. “Sunshine on Leith,” features the music of the Proclaimers and follows the highs and lows of two friends as they return home to Leith from the army. The film is produced by Andrew Macdonald and Allon Reich for DNA, and Arabella Page Croft and Kieran Parker for Black Camel Pictures. It is financed by the British Film Institute’s Film Fund, Creative Scotland and Entertainment Film Distributors, who have U.K. rights. Stephen Greenhorn scripted the film from his own legit musical. The cast also includes George McKay, Kevin Guthrie, Antonia Thomas and Freya Mavor. It’s Fletcher’s first film after his critically acclaimed “Wild Bill” earlier this year, and Macdonald’s first production in Scotland since Danny Boyle’s “Trainspotting” in 1996.