In this episode Boyd (Trevor Eve) gives his son's name as Joe. In later stories, where the son appears as a character, his name is Luke (played by George Rainsford).
Trevor Eve (Det Supt Peter Boyd) & Caroline O'Neill (Linsey Carr) also worked together on episode 1.4 Episode #1.4 (2015) of Unforgotten (2015) as Sir Phillip Cross & Joanna Bridges respectively.