Harley said it was the "most brutal" punishment he had seen Varty mete out to an opponent and he commended Menzies for his courage in coming out after the first two rounds.
"Brendan was absolutely brutal right from the start. Most people would have called it quits after the first round and that speaks volumes about Menzies and his sheer courage as a fighter."
Harley said Menzies suffered "some serious damage" during the fight although Varty had come away with only a cut below one knuckle and swollen wrists.
Elliot Connery, a Harley's Kickboxing Gym novice fighter, completed his ring debut at the same tournament on Saturday in a non-contest bout against Hamilton Stormforce fighter Leo Gough.
Harley said Connery, at 56kg, acquitted himself well.