I have been accused of defamation and would like some

Hi there, I have been accused of defamation and would like some advice. Last Thursday, March 25, Parent A phone me to say she had had an enrolment interview at a school my children used to attend. She told me that the principal had adjusted her son’s collar during the interview and run his fingers along his neck in a way that made both her and her son feel uncomfortable. Her words were that it was weird and creepy.
On Friday March 26, I told this story to Parent B. Parent B’s mother overheard this conversation, and then she told her hairdresser later that day that I have said the principal ‘inappropriately touched a child’. The hair dresser has then spoken to the principal. The principal called Parent A to discuss the details of their interview and asked what made her uncomfortable. Parent A told the principal that adjusting her son’s collar was the cause of her concern.
On Saturday March 27, I received an email from the principal stating that he would like an unreserved apology for defaming him and that he will take into consideration such an apology when seeking financial damages.
I would like to know the applicability of the defence of opinion. Given that the issue of consent is prominent in the public sphere and a routine conversation had between myself and Parent B, I am of the opinion that it is inappropriate to touch a child without their or their parent’s consent. Parent A is of the same opinion.
I also believe that my statement was a statement of truth.
The principal has given 7 days to respond in his letter, despite the act stating that I have 28 days to respond.