In the first instance you should instruct your solicitor to issue a cease and desist letter to this person demanding that they do not repeat the allegations and that they withdraw the allegations by way of a letter of apology. If they don't do this then your remedy is to issue proceedings. That of course is very expensive and may not be an option that you would wish to follow. Happy to discuss. I hope that helps. Please leave a positive rating so that I am credited for my time.