Complex sentence: Her maternal grandmother, Dora Paton, was a dairy maid at the Balmoral Royal Estate and her maternal grandfather, William Ferguson, was a gamekeeper at Balmoral who on one occasion danced with The Queen.
Split into simpler sentences: Her maternal grandmother, Dora Paton, was a dairy maid at the Balmoral Royal Estate. Her grandfather, William Ferguson was a gamekeeper at Balmoral and on one occasion danced with The Queen.