Captain's challenges should only be permitted for decisions causing a stoppage where play is to be restarted, i.e. a penalty, line drop-out, scrum. The stoppage from the referee before full-time was not a stoppage resulting from a decision he had made, nor was it a stoppage which would result in a structured restart of play. Therefore, captain's challenge should not have been permitted at all.
You talk about precedent being set. Imagine the precedent of players now calling for a referee to blow a "short" whistle for a random stoppage of play after a tackle has been complete to captain's challenge the play before. Or would this only apply to the "short" whistle before fulltime? How would that work? You can only challenge the play before fulltime or halftime and not any other play before? So effectively, you're challenging the full time siren? Annesley misinterprets his own rules and should be sacked solely for the absolute bollocks he spewed in that press conference earlier today