4. Correction of errors---Regulation 12 of the principal regulations is hereby amended by revoking subclauses (2) and (3), and substituting the following subclause: ``(2) The Registrar shall refuse to register an instrument containing a correction unless--- ``(a) The correction has been effected by deleting the words or figures written in error, and writing the correct words or figures above them; and ``(b) Where the correction affects or could effect the interests of any signatory of the instrument, it is initialled or signed by each signatory of the instrument, and by either that signatory's witnesses (if any) or a solicitor acting on that signatory's behalf in the transaction; and ``(c) Where the correction affects or could affect the interests of any person receiving the benefit under the instrument (not being a signatory of the instrument), it is initialled or signed by each such person or a solicitor acting on the person's behalf in the transaction.''