I wouldn't go as far as 'should have', but it was certainly a decent chance. I actually thought the side foot volley that he put inches wide right at the end was a better chance.
I hate this 'should have scored' thing anyway. You hear it all the time from TV pundits. "He really should have...
The cross got up higher than he expected, and he'd committed to going for it with his foot [knee]. This turned it into a difficult chance. If he'd stooped to head it, I'm sure he'd have scored.
The 'kick' and 'headbutt' suggestions are bizarre and are clouding the issue.
Call it a shove or a clump or a push or a punch, or whatever you like - Edwards made contact with Barnes' head with his hand. That much is FACT, and it was absolutely a straight red.
How much pain he actually...