Continuity mistake: In several episodes of the early seasons, Carson is said to have once been part of a music hall song-and-dance team with Charlie Grigg, who comes to Downton to blackmail Carson. But in later seasons, Carson is said to have come to Downton at a young age, serving as a hall boy.
Continuity mistake: Every letter's handwriting looks the same - no matter who wrote it.
Answer: Lord Sinderby purchased the house, furnished and appointed, from someone else, complete with staff that come with the home (some of whom aren't happy to be working for a Jewish family). He bought the title, as well. If the artwork featuring Jesus is valuable, he might keep it. Also interesting, his ancestors Anglicized their name, though he is proudly Jewish.
Michael Albert