Below is From history of rule changes which I found on the net. Only reason I recall and was pretty sure it wasn't for Birt, it is that I remember the change and was 4 y o when Birt retired!
Interesting history players in the 1939s would routinely just drop the ball when tackled to win a holding the ball free so the "no drop" rule came in in the 30s. But guys like baldock and Bartlett in the 60s (no doubt Birt) used the bounce til the below:
"Adjustments made to the rules in the late 1970s created the definitions currently enshrined in Law 15.2.2, removing the ability for players to bounce the ball or handpass to themselves as ways to avoid holding the ball free kicks or win holding the man free kicks. Richmond footballer Kevin Bartlett was particularly well known for using these tactics to avoid being penalised for holding the ball, and the rule changes are generally associated with his play."