Law 6 A 5 Altering a decision, leads me to now think I was correct in sticking with awarding the try.
let me throw a different law into the mix:
[LAWS]6.A.5 REFEREE ALTERING A DECISION
The referee may alter a decision when a touch judge has raised the flag to to signal touch.[/LAWS]
[LAWS]6.B.5 (d) When to lower the flag. When the ball is thrown in, the touch judge or assistant referee must lower the flag, with the following exceptions:
Exception 1: When the player throwing in puts any part of either foot in the field of play, the touch judge or assistant referee keeps the flag up.
Exception 2: When the team not entitled to throw in has done so, the touch judge or assistant referee keeps the flag up.[/LAWS]
There seems little point in keeping the flag up if the referee is not entitled to act upon it. What if the ref has awarded a knock-on from the improper throw-in, then notices the TJ's flag still up? Is he prevented from changing his decison? We also need to recognise that very few of the decisions we make result in the blowing of the whistle. By the time the ball is caught in the lineout, we have decided that the throw was taken from the right place, by the right team, without a dummy motion, without any early jump, without a foot in touch, that the ball travelled 5m and the throw was straight. We've made all these decisions - are we now prevented from acting on the TJ's flag because our second decision was wrong? If so, the law is inoperative.