Every programme here correctly identified Edward, apart from anything else at each of the events where he was photographed, they were given the attendees beforehand.
I am truly puzzled by your report from a TA member, he would have seen both William and Edward in attendance and known the different cap badge and rank insignia. Contrary to the commonly held belief, TA members are not thick and are fully trained up members of the forces. The RF had all retired into Whitehall before the march past and unless the TA members were in uniform, they would neither have given nor recieved a salute from an officer in uniform.