I believe that a few years ago the ranks of the Category 1 referees in Scotland included a Professor, no less. Indeed, I have heard him speak on the radio in his professorial capacity.
I have always found it slightly odd that German referees who are Doctors are given their title, while undoctored referees receive no tokens of respect whatsoever, receiving surname alone without first name, initials or Herr/Frau. Italian referees are also referred to by surname alone, but reference (and even address) by surname is widespread there. British referees traditionally got their initials and often Mr (or, where appropriate Dr/Rev./ rank in the armed forces), though first names are now taking over; I still find it vaguely disrespectful when referees are referred to on this forum by surname alone. French referees get the title M(onsieur), and even in the Soviet Union referees were normally given a more respectful version of their names (first name + patronymic + surname) than mere players, who had to make do with first name + surname or surname alone.