The men (Lord Grantham, Matthew, Branson and Sir Anthony) are having after-dinner cigars, and Lord Grantham talks about how Branson is their "tame revolutionary." Considering Sir Anthony was there for Branson's Roofie Realtalk, I don't think he's likely to forget that he's got a political bent to him. Branson and Matthew then head off for a game of billiards (it's a nice sartorial touch that, while Branson is dressed up, he's in black tie while the others are in white), leaving Lord Grantham to tell Sir Anthony that they're getting used to Branson and he hopes he will too. I don't think there's any indication that Sir Anthony has social issues with like, anyone, but I think Lord Grantham was just fishing for something to say. Sir Anthony senses it, offering that they haven't really spoken since everything was settled with Edith. He goes on that he understands why Lord Grantham was against the match, but he hopes Lord Grantham believes his sincere intention to try to make Edith happy. Lord Grantham does and adds that his objections were never personal, so Sir Anthony's like, no, of course not -- it's just that I'm kind of a cross between the Hunchback of Notre Dame and Methuselah? Lord Grantham replies that "the thing is done," so he's continuing to go along without expressing any enthusiasm, prompting Sir Anthony to ask him directly if he's happy about the union. Lord Grantham: "I'm happy Edith is happy; I'm happy you mean to keep her happy. That is quite enough happiness to be going on with." Even without Lord Grantham's "I'm so happy my chest might explode" comment about Mary and Matthew's wedding to most unfavorably compare it to, the short version of that answer is "No," and Sir Anthony looks a bit wounded and not in his hand for once. Honestly, I don't know if this is a stratagem at this point, but without Lord Grantham's extremely thinly veiled disapproval, I think the events of this episode would have gone differently.
Mrs. Hughes is talking about some last-minute changes to the wedding menu as Carson trails behind her like a nervous mother hen. She doesn't notice his concern until he tells her he just doesn't want to see her get tired, at which point she noticeably stiffens, and that's saying something among people whose posture is generally ramrod straight. She turns and asks to whom he's been speaking, but he's like, um... no one! Speaking? Where am I? Who am I? Mrs. Hughes lets it go, but if I were Mrs. Patmore, I'd hide in the meat larder the next time I heard her coming.