BBC One period detective drama Father Brown airs its big finale tomorrow afternoon, with fans tuning in to watch Chief Inspector Edgar Sullivan wed Isabel Devine in a highly-anticipated ceremony. However, fans may not be aware that the episode features a surprise cameo from the show's composer Debbie Wiseman - who has strong links to the Royal Family . In a behind-the-scenes look at the finale exclusively shared by The Mirror , composer Debbie reveals that she pops up in the episode as the