The film “The Ballad of Wallis Island” tells the story of Charles, an eccentric lottery winner who uses his money to hold a private concert on the remote Welsh island where he lives. The band he hires is his favourite group of all time: the fictional folk rock duo McGwyer Mortimer. The only problem is they haven’t spoken in years — and the concert is just for Charles. British poet and comedian Tim Key stars as Charles and co-wrote the movie, which is based on a short film he made in 2007. Earlier this year, he joined Tom Power to talk about the project and why it took 18 years to turn his short into a feature. Plus, he reveals how he persuaded Hollywood A-lister Carey Mulligan to get on board.