Could the ref have rescinded the yellow if he thought it was unjust after the TV viewing and changing the way of the penalty.
Personally I don't think so. Care was given yellow for bringing down a maul and England had been forewarned that further penalties on their defence line would result in a card. I think any foul play occurred after the penalty offence. Could have seen the Welsh 18 carded as well but wouldn't affect the Care decision. That's how I would have called it anyway.