His transition required thirteen operations and took place over four years, with no one the wiser. Dillon went on to be a surgeon himself, and traveled the world with various naval vessels for six years, living life as a man, with no one suspecting his origins. 

He was ultimately outed because of his nobility.  There are peerage records that are made of everyone's descendancy and changing one’s names in those had been impossible and eventually someone noticed the discrepancy. 

After living as Michael Dillon for fifteen years, he was onboard a ship when he got a cable from England. It was from The Daily Express as said “Do you intend to claim the title since your change-over?”

Sources:

Out of the Ordinary by Michael Dillon

Info:

http://illreputepodcast.com