Big Finish has, over the years, welcomed an eye-popping array of A-listers through its doors. John Hurt, Derek Jacobi, Sheridan Smith, Michael Palin, Nicola Walker, Hugh Bonneville, David Warner, Simon Pegg: all have at some point journeyed down to one of the company’s four UK recording studios. “Benedict Cumberbatch did a Doctor Who story with us in 2008,” recalls senior producer David Richardson, “and we gave him a longer lunch break so he could pop off to audition for Sherlock”.