Complex sentence: In historical terms, gonks were one of the earliest toy crazes in post-war history, though losing the Toy Retailers Association's' Toy of the Year'title to the' Action Man' dolls.
Split into simpler sentences: In historical terms, gonks were one of the earliest toy crazes in the post-war period. They lost the Toy Retailers Association's' Toy of the Year'title to the' Action Man' dolls.