27. Where—
(a)notice given under rule 19 in a cause or matter relates to a statement which is admissable by virtue of section 1 of the Civil Evidence Act, and
(b)the person who originally supplied the information from which the record containing the statement was compiled, is not called as a witness at the trial or hearing of the cause or matter, and
(c)none of the reasons mentioned in rule 22 applies so as to prevent the party who gave the notice from calling that person as a witness,
no other party to the cause or matter shall be entitled except with the leave of the Court, to adduce in relation to that person any evidence which could otherwise be adduced by him by virtue of section 4 of the Civil Evidence Act unless he gave a counter-notice under rule 23 in respect of that person or applied under rule 23 for a direction that that person be called as a witness at the trial or hearing of the cause or matter.