The first thing you must do is establish what the Works Information actually is. A defect is, in general, any part of the works which does not comply with the Works Information.
As a simple example, the Original Employer WI says use an adequate fixing mechanism, the detail submitted and accepted shows 4 screws used in the fixing, on site they install 2 because they consider that is adequate albeit less than the detailed accepted design shows. Here we will then be looking at clause 11.2(5) second bullet as the definition of a defect. This is a piece of work designed by the contractor which is not in accordance with the design which the PM accepted. Therefore the work is defective.
As a simple example, the Original Employer WI says use an adequate fixing mechanism, the detail submitted and accepted shows 4 screws used in the fixing, on site they install 2 because they consider that is adequate albeit less than the detailed accepted design shows. Here we will then be looking at clause 11.2(5) second bullet as the definition of a defect. This is a piece of work designed by the contractor which is not in accordance with the design which the PM accepted. Therefore the work is defective.