You know who doesn’t get enough (or any) appreciation, but definitely deserves some?
Because this man managed to hide from the Master for the entire Year That Never Was.
He wasn’t even taking Martha seriously at first when she called him and told him to hide. The last thing he said to her was “Shut up.” and laughed. But then the phone call got interrupted by Saxon, Martha screamed “Let them go!” and the Doctor took the phone away.
Leo had said he was in Brighton and Martha suggested he hides at his friend Boxer’s house, but the Master was already listening the whole time. So Leo not only hid, but he definitely got out of Brighton since he knew Saxon now knows that that was where he was.
And he protected his girlfriend and daughter too. They were out walking in public when Martha called, so they definitely had to drop everything and hide immediately.
That night, Jack and Martha were happy that there was no sign that Leo had been found yet. He never ended up on the Valiant at any point during the rest of the year. He and his family were safe.