56.—(1) A party to proceedings under Part 2 of the Act who wishes to adduce expert evidence (whether of fact or opinion) in the proceedings must, as soon as practicable—
(a)serve on the other parties a statement in writing of any finding or opinion which he proposes to adduce by way of such evidence; and
(b)serve on any party who requests it in writing, a copy of (or if it appears to the party proposing to adduce the evidence to be more practicable, a reasonable opportunity to examine)—
(i)the record of any observation, test, calculation or other procedure on which the finding or opinion is based; and
(ii)any document or other thing or substance in respect of which the observation, test, calculation or other procedure mentioned in sub-paragraph (i) has been carried out.
(2) A party may serve notice in writing waiving his right to be served with any of the matters mentioned in paragraph (1) above and, in particular, may agree that the statement mentioned in sub-paragraph (a) may be given to him orally and not served in writing.
(3) If a party who wishes to adduce expert evidence in proceedings under Part 2 of this Act fails to comply with this rule he may not adduce that evidence in those proceedings without the leave of the court, except where rule 57 applies.