How likely is a criminal conviction from the magistrate's court to be quashed after an appeal?

A mentally unstable man from our old neighbourhood was convicted of racially aggravated abuse and threatening behaviour against me and my partner in court last month, he was sentenced and a restraining order was put on him. However, he has since decided to appeal his conviction and we are set to go to court again next month. Of course I understand that all cases are individual and the outcomes are different, but does anyone know statistically how many convictions are usually quashed? I am terrified of this man and the fact that the restraining order may be lifted against him.