12. (1) The Board of Revenue may, on their own motion or on an application, call for the record of any proceeding of the assessing authority or the appellate authority by whom the case of appeal was decided if it appears to have exercised jurisdiction not vested in it by law or to have acted in the exercise of its jurisdiction illegally or with substantial irregularity, and may pass such order in the case as they think fit:
Provided that no such application shall be entertained in any case where an appeal lay against the order but the applicant failed to prefer it within the time prescribed therefor:
Provided further that the Board of Revenue shall not pas any order prejudicial to any party without giving him a reasonable opportunity of being heard.
(2) The application under sub-section (1) shall be made within one year from the date of the receipt of the order complained of, but the Board of Revenue may on proof of sufficient cause, entertain an application within a further period not exceeding six months.