3.11.12—(1) When on the trial of a petition complaining of an undue return and claiming the office for some person, the respondent intends to give evidence to prove that that person was not duly elected, such respondent shall, 5 days before the day appointed for the trial, deliver to the sheriff clerk, and send by first class post to the petitioner and the Lord Advocate, a list of the objections to the election upon which he intends to rely.
(2) No evidence shall be allowed to be given by a respondent in support of any objection to the election not specified in such list except by leave of the sheriff principal granted upon such terms as to the amendment of the list, postponement of the trial, and payment of expenses as to him may seem fit.