Choose the most relevant primary category, in this case I would pick the default "carpet cleaning services."
Unless there is another category or service that is not described by that one category, I would not add additional ones. Your example seems like your trying to stuff as many keyword as possible, including synonyms.
For example, "Carpet cleaning hire" is essentially a duplicate of carpet cleaning services, but if they also do upholstery, you could add the category upholstery cleaning. Having less (or only one) category will place the most weight on those services.
