What is the importance of the Montblanc pen given to Kay by his consultant in the nonfiction book, This Is Going to Hurt?

At the end of Kay's time at his second post as a registrar, his consultant, Mr. Lockhart, offers him a Montblanc Pen as a parting gift, highlighting the theme of recognition prevalent throughout Kay's writing. This is one of the first instances in which a colleague acknowledges Kay's hard work.