Will Thorne Staff WriterThe Apple spy drama “Slow Horses” has added a quartet of eye-catching names to its cast.Joining Gary Oldman in the lead will be Kristin Scott Thomas, Jack Lowden, Jonathan Pryce and Olivia Cooke. News of the castings comes over a year after the small screen adaptation of Mick Herron’s Slough House books was first announced.“Slow Horses” follows a team of British intelligence agents who serve in a dumping ground department of MI5 – Slough House.