Vera looks at an Ordnance Survey map when tracing Lizzy's movements. This was a real map of the area between Newcastle, Prudhoe and Consett, with a few name changes: the town of Brignull was in reality High Spen, and Swann Farm was in reality Broomfield Farm.
This episode is written by Sally Abbott and stars Grace Hogg-Robinson. They also worked together on BBC series The Coroner (2015).