When Henry is talking to Foster about the bank turning down the request, he stands behind Foster's chair and slaps his hand on top of the chair back. But in the next shot, Henry's had is at his side.
The carolers sing "God rest you, merry gentlemen," but in Edwardian England they would have sung "God rest ye."
The artist's studio is obviously on the top floor, as it has a skylight. However, on entering the building, which has several stories, he says that the studio is only one flight up.