Where, during the trial of a person accused of a crime under chapters XIV or XX , or a crime under section 170A or relating to family violence within the meaning of the Family Violence Act 2004 , there is evidence which tends to suggest an absence of complaint by the person upon whom the crime is alleged to have been committed or which tends to suggest delay by that person in making a complaint, the judge shall–

(a) give a warning to the jury that absence of complaint or delay in complaining does not necessarily indicate that the allegation that the crime was committed is false; and

(b) inform the jury that there may be good reasons why such a person may hesitate in making, or may refrain from making, a complaint.