The final 13 episodes, combined series 4 and 5, were actually shot at various locations within the Republic of Ireland, mostly around the Dublin-Wicklow area, some with none to major digital set dressing enhancement. The city wall map in the office, in Series 4 and 5, is actually Dublin City, turned upside down.
A total of seven actors who have played major characters on 'Primeval' (Lucy Brown, James Murray, Andrew-Lee Potts, Juliet Aubrey, Ciaran McMenamin, Laila Rouass and Anton Lesser) have also appeared in the popular TV series 'Midsomer Murders'.
Ben Miller (James Lester), Hannah Spearritt (Abby Maitland) & James Murray (Stephen Hart) all appeared on episode 2.6, A Dash of Sunshine (2013) of Death in Paradise (2011) as DI Richard Poole, Lily Shaw & Ronnie Stuart respectively.
Wellington Zoo scenes were filmed at London Zoo and Whipsnade Zoo.
Two of the main characters are named Sarah: Sarah Page and Abby (Sarah) Maitland.