'He was sat/stood' always makes me twitch as being ungrammatical. One of the things I've been proofreading recently are car sales training workshop manuals (yes, really; you wouldn't *believe* what I could tell you about the Hyundai Five Point Walk-Around!), and one of them regularly says (for test drives) that 'the handover should take place with the customer sat inside the car' or 'perform [this sales technique] while stood behind the car', and I always, ALWAYS, correct it. *twitch*