Marshall

Simple

It's a red card for violent conduct even if he hasn't made contact the intent was crystal clear which under the rules of the game means a red card

The penalty 100% isn't one and should be a free kick to us and a yellow card to Derbyshire for holding Marshall back

The biggest failure here is the linesmans inability to spot that when he is level with play looking at the incident he should be pulling the referee aside and telling him it's a foul by Derbyshire so no penalty free kick to Cardiff but the red card stands as the keeper kicked out