Any public inquiry into the activities of the JFIT would be expected to examine the extent to which it was supervised by military lawyers. It is now known that at least some of the training material used by F Branch at Chicksands between 2003 and 2005 escaped the scrutiny of the training centre's in-house lawyer, Brigadier David Yates, who told the Mousa inquiry that he did not "have the capacity" to check it.
This is important because, as the piece also points out, most of the interrogators were reservists. They would have gone first of all to the Chilwell mobilisation centre to do fitness tests, draw additional kit, get their vaccinations, complete their admin, and to do refresher courses on things like first aid, marksmanship, and anti-terrorist precautions. Then, later, they would have gone for a period of pre-deployment training, which would concentrate on preparing for their specific role in Iraq, before finally shipping out via South Cerney and RAF Brize Norton. It would make sense if the reservist intelligence people were sent to their trade's headquarters, which for most of them would also be their unit's peacetime depot, for their specialised pre-deployment course. (I think I have the process right, but several readers can correct me.)
Now, we also know that the Americans began with the torture in 2002, and that Major-General Geoffrey Miller was transferred from Guantanamo to Iraq with his infamous directive to "Gitmo-ize" the detention camps in the summer of 2003. So, where did this documentation come from?