Simon looks like a referee running low on confidence. 2 poor decisions. I could not work out whether his visual explanations were bluff or bluster as on Bertrand's tackle the man was played long before his foot went anywhere near the ball and the distance from the attacker was such that to try and say he headed it leaves you with even less credility.
Howard Webb was always a fan of decisions "not coming as a surprise". I think the chalked off goal falls very much in that category