Complex sentence: The couple appeared to have a happy marriage with their two daughters, and presenting a united outward appearance during the late 1980s; the Duchess was seen as refreshing in the context of the formal protocol surrounding the Royal Family.
Split into simpler sentences: The couple appeared to have a happy marriage and had two daughters together, presenting a united outward appearance during the late 1980s. The Duchess' personal qualities were seen as refreshing in the context of the formal protocol surrounding the Royal Family.