There's No Place Like Home - S28-E16
Character mistake: The old photo of Sylvia and her friend shows them in RAF uniform. Sam, who is a serving British Army officer and could be expected to recognise the very obvious differences between the uniforms, keeps referring to Sylvia being in the Army and Sylvia does not disagree with her.
Character mistake: Charlie says that Iain has been a paramedic for ten years. Iain actually joined as a student paramedic in August 2013 immediately after leaving the Army (in which he was an infantryman, not a medic). As 'Casualty' operates in real time and this episode was shown in February 2019, Iain has therefore been a paramedic for only five and a half years.