7.—(1) Subject to paragraph (2) and articles 8 and 9, the amount of each assessment appearing in an assessment notice served by the Board is due and payable by the employer to the Board one month after the date of the notice.
(2) The amount of an assessment is not recoverable by the Board until there has expired the time for appealing against the assessment allowed by article 9(1) and any further period or periods of time that the Board or an employment tribunal may have allowed for appealing under article 9(2) or (3) or, where an appeal is brought, until the appeal is decided or withdrawn.