Forms of address
Dramas set in the late 19th-early 20th century never get this detail right. I'm sure Lizzie would have addressed her parents-in-law as Mr and Mrs Mottershead, not Albert and Lucy. I suppose scriptwriters, if they're aware of the usage, think it would make their characters seem cold and stilted to modern ears not to be on first-name terms with family and friends.
Also, the vicar would have been addressed as Mr Webb or Vicar, not Reverend.