Complex sentence: Several extras in the film were then players of Raith Rovers, including future Celtic player Didier Agathe, a club Duvall went to see regularly to learn from John McVeigh, the manager, on whom his character was based.
Split into simpler sentences: Several extras in the film were then players of Raith Rovers, including future Celtic player Didier Agathe. Duvall regularly went to see Raith Rovers to learn from John McVeigh, the manager, on whom his character was based.