I have made some changes to the Category services / mappings:
The association from Category and CategoryOption has been changed from unidirectional many-to-many to bidirectional one-to-many.
The content in CategoryOptionService, CategoryComboService and CategoryOptionComboService have been merged with CategoryService.
The idea is that we make the API lighter and usage simpler for the Category related functionality in the sense that you can work with one rather than four services. I don’t think this breaks with the one-class-one-responsibility principle as these classes are highly related. Also, the class still has less than 700 lines and is manageable.