If it contained things which were blatantly not true and the contents would lower your esteem in the minds of right-thinking people, then you have been defined and the culprit has committed libel by publishing a statement to 3rd parties.
Unless you want to spend tens of thousands of pounds, a solicitors letter threatening court action but not actually going ahead with it is probably as far as you would want to go. The solicitor would threaten legal proceedings unless there was an apology and the allegation withdrawn.
If this is part of a campaign which has happened on more than one occasion, then it could be harassment and that is a police matter.
Can I clarify anything for you?
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We can still exchange emails. Best wishes. FES.