How high up the social class chain can my fiction character be?

I am writing a story. My character is supposed to come from a very wealthy family in England. I am wondering how high up the class system he could be without really changing anything in my story. The family is very old and he inherits a large estate after his grandmother dies. She was of the class that she would have been presented to the queen at the appropriate age, entertained on a very large scale, etc. I've tried to research aristocracy, etc. but it's very complicated. In the story his father tries to take the estate but the grandson fights him (legally in court) and wins and it makes headlines. After that he's an heir to one of the oldest and largest estates in the country. But, how much power could his family, or even he, have without being nobility? He lives a pretty reckless wild life but he's rich in the second half of the story and somewhat powerful. I know some names go back thousands of years, surnames, but they don't necessarily signify anything. A million could have the name Bainbridge for example but to have an old name, a family name, a family crest, how would that work? Any suggestions on what he and his family would be are very appreciate.