(a) Questions which effect credibility by attacking character but are otherwise irrelevant to the actual enquiry, shall not be asked unless the cross-examiner has reasonable grounds for thinking that the imputation is well-founded or true.
(b) Where a question relates to matters so remote in time or of such a character that it would not materially affect the credibility of a witness, it shall not be put.
Rule 14. Questions irrelevant to actual enquiry not to be asked.