He did an interview on Graham Norton a little while ago and he was asked if he ever found himself doing the accent without effort, just speaking that way. No was the answer, every word, every sentence was hard work for him. I thought more of him after hearing that. Agree with what you said about itHouse was like so many great shows, superb until the last series or 2 and then it went off the rails.
Credit to Hugh Lawrie that some people had difficulty believing he was not American.