When citing a book (Harvard) what should year be?
You write down the year in which the particular book that you are holding in your hands was published -- not any earlier or later reprints, not the first publication.

Since you are citing a literary work, and since that work has been republished many times, the date of its publication is not very meaningful. You may be better off using an author-title format (MLA) rather than an author-date format (Harvard).