mick, seems to me that if your partner is ball side but not officiating the ball that you need to stay on the ballhandler. The fact that the L is ball side doesn't necessarily mean he's leaving his off-ball responsibilities. I'm sure you know that, tho. It's important for the T (or the C, in 3-man) to continue to officiate the ball until the L has "accepted" the play. That means the L is in position and is officiating the ball.
Preaching to the choir, I know. . .
Chuck