Complex sentence: Another of Kate's cousins, Elinor Lupton was Leeds Lady Mayoress "suo jure" in 1943; her Lord Mayor being Albert Kitson's first cousin, Miss Jessie Beatrice Kitson.
Split into simpler sentences: Another of Kate's cousins, Elinor Lupton was Leeds Lady Mayoress "suo jure" in 1943. Playing Lord Mayor to Elinor's Lady Mayoress was Albert Kitson's first cousin, Miss Jessie Beatrice Kitson.