4Every return, in addition to containing the accounts mentioned in paragraph 2 above, shall contain a copy of the report made by the auditor or auditors of the trade union or employers' association on those accounts under paragraph 18 below and such other documents relating to those accounts and such further particulars as the Registrar may require, subject in the case of the accounts contained in the return to such modifications (if any) as may be necessary to secure compliance with paragraph 3 above.