Who played sigfrieds wife Caroline in all creatures great and small?

In the television series "All Creatures Great and Small," Siegfried Farnon's wife, Caroline, was portrayed by actress Mary Hignett. The show, based on the books by James Herriot, aired in the 1970s and featured a variety of memorable characters in the veterinary practice setting. Mary Hignett's portrayal contributed to the series' charm and appeal.