You missed the point, if they had of been plotting the position on a chart, taken from the Lat/Long readouts, then they would have known where they were, rather thinking they knew where they were.
So why wasn't that part of the SOP? Once again proof positive of the lackadaisical approach to the entire operation by both the airline itself, and the CAA. Everyone in the country, had they known the SOP, would have known they were not being followed, because it was featured in all the media. For the CAA to say they didn't know SOP wasn't being complied with is just disingenuous at best, and an outright lie at its worse. Same with the airlines management. A classic case of the "Normalisation of Deviance" concept.