Fergus Wilson was found guilty of assault by beating in April 2014 and fined more than £1,500 for hitting 31-year-old estate agent Daniel Wells.
Mr Wilson, 67, admitted storming into PLS (Property Lettings and Sales), Folkestone, and shouting: “Right you little s***” but denied hitting Mr Wells in the temple and knocking him off his chair.
In August last year, Mr Wilson, who owns thousands of properties in Ashford, Folkestone and Maidstone with his wife Judith, appealed at Canterbury Crown Court, but the original conviction was upheld.
He said he was not happy with the police report and will keep fighting.
He said: “They found a number of things wrong but aren’t going to do anything about it.
“I will follow it up with a private prosecution, but not every one would have the resources to do that.
“I will pursue this complaint to the ends of the earth, and that means Strasbourg [the French town home to the European Court of Human Rights.]”