"The Tribunal shall have power to review and to revoke or vary, by certificate under the Chairman's hand, any decisions on the grounds that - [(a), (b) and (c) are not relevant to the present case] (d) new evidence has become available since the conclusion of the hearing to which the decision relates, provided that its existence could not have been reasonably known of or foreseen; or (e) [that the interests of justice require such a review].
"(3). an application for the purposes of paragraph (1) of this Rule may be refused by the President or by the chairman of the tribunal which decided the case or by a Regional Chairman if in his opinion it has no reasonable prospect of success.
"The parties are entitled to be told why they have won or lost. There should be a sufficient account of the facts and of the reasoning to enable an appellate court to see whether any question of law arises"