Desmond Llewelyn was not the first choice for the role of Q.
Peter Burton preceded Llewelyn as Q but for only one film,
Dr. No (1962). In that movie, he was known as Major Boothroyd and Armourer. Llewelyn was only referred to as Major Boothroyd once in the James Bond movies, and that was by
Roger Moore in the
The Spy Who Loved Me (1977).