Thanks. The rules are ridiculously complicated, but I suspect you're correct in your assessment. The footage of the incident is at about 2.20 of the highlights I posted.
Well, again, I disagree with you and @Triggaaar and no doubt many other BHA fans that are certain they can objectively view these things. It hit him from centimetres away
https://www.skysports.com/watch/video/sports/football/12847490/brighton-3-3-brentford-premier-league-highlights
The right decision was made in the end. It was hand ball and a penalty, but not deliberate and, to the extent that I understand the rules, warranted a yellow.