If an agent alleges that a determination under paragraph 4 of Schedule 16A was excessive because of some error or mistake in a return made by him under paragraph 2 of that Schedule, he may by notice in writing at any time not later than six years after the end of the year of assessment 1989—90 make a claim to the Board for relief.

On receiving the claim the Board shall inquire into the matter and having regard to all the relevant circumstances of the case, but subject to paragraph (3), give by way of repayment or otherwise such relief in respect of the error or mistake as is reasonable and just.

No relief shall be given under this regulation in respect of an error or mistake as to the basis on which the syndicate profit or loss ought to have been computed where the return was in fact made on the basis or in accordance with the practice generally prevailing at the time when the return was made.

An appeal may be brought against the decision of the Board on the claim, by giving written notice to the Board within 30 days of receipt of written notice of that decision and the Special Commissioners shall hear and determine the appeal in accordance with the principles to be followed by the Board in determining claims under this regulation; and either the appellant or the Board shall be entitled to require a case to be stated under the like provisions as are contained in section 56 of the Taxes Management Act 19709 but only on a point of law arising in connection with the computation of profits or losses.

In this regulation “return” includes the documents referred to in paragraph 2(1)(b) and (c) of Schedule 16A.