In the Scotland training scene, Mac, the instructor says "..and for those of you who don't know me, you're in for a big f***in' surprise" and "...now let's try for our first heart attack, shall we?". These lines are almost identical to those spoken by RSM Sandy Young (Jack Watson) in The Wild Geese (1978).
The name of the the real life military outfit that James Bond creator fought for which is depicted in the film was the "30 Commando Unit" which was also known as the "30 Assault Unit" and informally also known as Ian Fleming's "Red Indians".
Ian Flemings "30 Commando Unit" was a precursor to the elite forces in the UK such as the SAS (Special Air Service).
The code name of the secret mission was "Operation Grendel" and bears resemblance to the real-life "Bruneval Raid" which was officially also known as "Operation Biting".
Director Adrian Vitoria has said of this film: "We had commandos, real British commandos, work on this project. They helped us and they played members of the SS. They are all ex-military men who have worked in Iraq and Afghanistan and have seen real action. Their contribution to this film was great and I think if anything it's given them an opportunity to see what we do in filmmaking and understand why it takes so long and why we can't include every single detail in the finished edit. They've educated us in the workings of warfare".