If you were referring to a different series or the original source material:
: With Louisa back at work, the couple struggles with finding a nanny. Their first hire, Mel, is dismissed by Martin after he bluntly diagnoses her with an infection caused by obesity. [S6E2] Guess Who's Coming to Dinner
: In an effort to be social, Martin invites Dennis Dodd (the chair of school governors) and his wife Karen to dinner without consulting Louisa. The night turns awkward when Martin suspects Dennis is drunk, unaware that his slurred speech and physical clumsiness are actually symptoms of Parkinson’s Disease . If you were referring to a different series