Slow Horses season six review – it gets harder to enjoy Gary Oldman’s spy thriller every year

<p>The show’s creator has gone, it’s been retooled as a conventional thriller and it feels like it’s starting to run out of ideas – even if it’s as slick and confident as ever</p><p>This is a new Slow Horses: season six is the first not to be guided by its creator, Will Smith, a wr