You're correct Nellie, QEII was a great Monarch and indeed, defended the Monarchy. Tony Blair was a big supporter of Andrew for trade envoy and pushed for it, Mandelson pushed it, too.
Andrew had just retired from the Navy, I believe and there still was the Fergie/John Bryan scandal hanging around. I believe the Queen wanted Andrew to hold an important position and be recognized for his work, he was the second son and the Queen's favorite, if the stories are correct. We'll never know her personal thoughts. I guess in one way she can't be faulted at the time for pushing for Andrew, she had no way of reading the future and what would happen in his handling of his position.