What is the significance of the substitution made by s.4, ibid., for cls. (2) and (3)?
The substitution made by s.4, ibid., for cls. (2) and (3) indicates a change in the previous clauses of the context. It implies that the original provisions in those clauses have been replaced or altered by the amendments introduced in section 4 of the respective Act. This could lead to changes in the legal implications, requirements, or procedures concerning the sale or purchase of goods or services as discussed in the context.