It's filmed in one location at Groot Drankensburg in Franschoek, South Africa
The patches worn by everyone read "IFAS", a play on the "ISAF" patches of the 'International Security Assistance Force's worn by actual troops in Afghanistan.
Each member of Bluestone 42 has a defined role: -Nick is the Commander and Ammunition Technical Officer (ATO) and is the technical expert on explosives Millsy (later Tower Block) is the ATO 2IC (Second in command) directly supports Nick as an ATO Bird is the detachment Signaller and is responsible for all communications between B42 and command Simon is the guard commander (directly responsible for Mac and Rocket) Mac and Rocket are force protection who are there to protect the rest of the detachment whilst they work.