Try, no try? The try was given and so it stands as a try to the crack of doom, but should it have been awarded?

Alby Mathewson, the Blues' scrumhalf, bursts ahead and is immediately tackled by Kieran Read. Mathewson gets to his feet and darts over the line for a try.

Would you have given it?

a. Was there a tackle?

Mathewson was grabbed by Read and brought to ground.

It was a tackle.

b. Was Mathewson held when he got up?

The referee called roll and Read obeyed. He released Mathewson.

He was not held.

c. Did Mathewson play the ball in the tackle as the law requires?

It is hard to see because he is not always visible.

d. Was Mathewson on his feet when he held the ball?

No. He eventually got to his feet  and then darted ahead.

Had he complied with the law?

15.5 THE TACKLED PLAYER
(a) A tackled player must not lie on, over, or near the ball to prevent opponents from gaining possession of it, and must try to make the ball available immediately so that play can continue.
Sanction: Penalty kick
(b) A tackled player must immediately pass the ball or release it. That player must also get up or move away from it at once.
Sanction: Penalty kick

No. He did not immediately pass or release the ball. He did not get up before playing the ball.

If you had not awarded the try, you would have been right - and Read would be happy to go on releasing the tackled player and rolling away.