Thanks Spook
It's always interesting to read the definitive version. This is what the rule book says about the play the ball -
Retire at play-the-ball (g) players of the side not in possession other than the player taking part in the play-the-ball and the acting half back are out of play if they fail to retire ten (10) metres from the point at which the ball is played or to their own goal lines. Players of the side in possession other than the player taking part in the play-the-ball and the acting halfback must retire behind their players involved in the play-the-ball or to their own goal line.
(h) having retired the distance prescribed in the preceding paragraph no player of the team not in possession may advance until the ball has cleared the ruck. A player who is out of play may again take part in the game when the advantage gained by not retiring has been lost.
My understanding of the term "cleared the ruck" is when the acting halfback has passed the ball but I don't recognise that as any part of a rugby league match.