The term Scarlet and Miniver refers to the state robes of medieval royalty. They were often made of miniver, a white fur, trimmed with scarlet, a richly dyed red cloth. It is of note that the term "scarlet" was also used to refer to someone flamboyant and possible immoral - particularly in relation to women. Thus, the in this story the title definitely refers to Eleanor's predilection for marrying royalty, first Louis VII and then Henry II; but it could also refer to her somewhat flamboyant, and by the morality of the times, somewhat immoral life.
Scarlet and miniver are just objects to describe one of the big characters in the novel. Scarlet and miniver describe queen Eleanor of Aquitaine's personalty. She has a lot of money and land but not a lot of patience. She also is a very annoying and all-that-thinking kind of person. When Eleanor marries Louis, son of Louis the VI, they are much diffrent. You might think that they would be alike because they both are rich and have stuff but they are not alike. Anyway, Eleanor always wears scarlet and miniver. You may be wondering what miniver is well scarlet is a robe that is scarlet colored to show royalty and miniver is a type of fur that, probalty back in Middle Ages was very expensitive. That is where the title A Proud Taste for Scarlet and Miniver is.