 At a party given by her sister Helen (Susan Penhaligon (qv)) in  the first episode, Laura (Judi Dench (qv)) is reading the novel  "Bouquet Of Barbed Wire", which had been dramatized for television  five years earlier starring Penhaligon. The edition Laura is reading  features Susan Penhaligon on the books front cover and Dench makes  a knowing reference to this by peering confusedly at the picture as  if to indicate the face in it looks very familiar to Laura