The Tall Stranger by D.E. Stevenson

Nell is worried about her friend, Barbie France, who has been very sick and is not getting better. When the doctor she works for accompanies her to the hospital in a thick fog, he recommends that Barbie recuperate in the country. Nell calls Barbie’s aunt, Lady Steyne, and Barbie is sent by ambulance to the Cotswolds to Underwoods to rest. Barbie misses her work for an interior decoration firm but it is wonderful to be spoiled by her Aunt Amalie and her companion, Miss Penney.