@Andrew_W-I NEC3 guidance notes say that work not done is included in the definition of a Defect. NEC4 guidance does not expressly say that, but every commentary I have read on NEC4 interprets the definition of a ‘Defect’ to include both work not done as well as work done incorrectly. As @Neil_Earnshaw says, the works start off entirely defective and are progressively made less defective as the contractor works its way to completion. As for notification, @Jon_Broome, I don’t think either the Contractor or the Supervisor have a choice but to notify, clause 43.2 places an express obligation upon them both to notify.
I also don’t think that defects that do not prevent Completion need to be minor. As long as the Defects don’t prevent the Client using the works, then Completion could occur. This could be the landscaping works to an office development which are left incomplete until the planting season. In that case the costs of carrying out that work would be disallowed, and that doesn’t seem particularly fair or collaborative and probably isn’t the intention.
But, as @Neil_Earnshaw says, the clause could have said ‘Defects notified after Completion’ and as it does not, we seem to be stuck with an unsatisfactory situation which some not to be named project management firms are taking advantage of.
I know you all know the above, I was just thinking out loud.