art 8 Payment of the levy
(1) Subject to the following provisions of this Order, the amount of each assessment appearing in an assessment notice served by the Board (the date of which shall not be earlier than 31st August 1987) shall be due and payable by the employer to the Board one month after the date of the notice. (2) The amount of an assessment shall not be recoverable by the Board until there has expired the time allowed for appealing against the assessment by Article 10(1) of this Order and any further period or periods of time that the Board or an industrial tribunal may have allowed for appealing under paragraph (2) or (3) of that Article or where an appeal is brought, until the appeal is decided or withdrawn.