Bravo Two Zero was basically a fog of war FUBAR. Their was miscommunication at several levels. Under normal circumstances it was probably not have mattered. They went in on foot because a SAS Trooper on foot is the next best thing to invisable. It should be born in mind that the documentary was done with the benefit of 20/20 hindsight. The people who make these documentarys are perfectly aware that SAS Troopers are, like all British Subjects, subject to the Offical Secrets Act. That means that for reason's of state, none of the members of the Bravo Two Zero team would be permitted to sue for liable.
And, at the end of the day, they were blown because they balked at killing a young boy who walked right over the top of them.