I work with a current FA refs assessor, he came to talk to me about it this morning as he knows I'm a Wednesday fan, he's good friends with Fridays ref and said he spoke to him last night.
He thought it wasn't a second yellow but could understand why it was given. Also said Wallace should've been red carded but the ref told him he didn't have a clear view and didn't send him off because it would've been guess work.
He also told me the ref had a falling out with wilder after the game