I am searching for British Royals who denounced their royalty and left home.?

I know that the British Government used to keep track of royals (legitimate and illegitimate) who left home and denounced royal life. They were essentially blacklisted and stripped of any titles/legitimacy. I am specifically looking for the time period between 1860 and 1880. My great-great-Grandfather often alluded to being a part of the British Royal family in rare conversations with his oldest children. In the past two years we have sent DNA from one of his youngest daughters (my great-grandmother) to be compared with Queen Victoria's and it is a match. I am not suggesting that he was a son of Queen Victoria (as her line is highly documented) but he is obviously a close relative and we are just trying to find where we tie for genealogical purposes. If anybody can help with this that would be fantastic.