You seem to have a lot going on!
I suggest that you should revisit the Defect notification and check that it covers what you consider the issue(s) to be and is clear. If unclear then I would issue a new notification or series of notifications if there are different issues. From your comments there appears to be a variety of issues ranging from level control to material compliance each of which I would treat separately.
Regarding the as built levels, the Contractor cannot unilaterally carry out design development. If the levels, when allowing for tolerances, are not in accordance with the approved design then it is a Defect.
It appears that you have taken advice from a subject matter expert and they have confirmed your position in respect of compaction, which is good. Have you shared this with the Contractor.
I think the matter over the second subcontractor may be something of a red herring, the Contractor remains responsible for providing the works in accordance with the Works Information (Scope).
You can point out to the Contractor that he is required to obtain approval prior to subcontracting and that you have reservations that the proposed subcontractor will not be able to Provide the Works and it will potentially result in a further Defect. You could refuse, see cl 26.2.
In respect of the Defect correction measures being proposed by the Contractor (“patching plaster”) you will need to consider what is set out in the contract and on that basis what is acceptable.
Having checked the notifications given, I would suggest that you make a clear list of the issues and have a meeting with the Contractor to agree a solution or that you will have to engage others to correct the Defects.
I suggest that you should revisit the Defect notification and check that it covers what you consider the issue(s) to be and is clear. If unclear then I would issue a new notification or series of notifications if there are different issues. From your comments there appears to be a variety of issues ranging from level control to material compliance each of which I would treat separately.
Regarding the as built levels, the Contractor cannot unilaterally carry out design development. If the levels, when allowing for tolerances, are not in accordance with the approved design then it is a Defect.
It appears that you have taken advice from a subject matter expert and they have confirmed your position in respect of compaction, which is good. Have you shared this with the Contractor.
I think the matter over the second subcontractor may be something of a red herring, the Contractor remains responsible for providing the works in accordance with the Works Information (Scope).
You can point out to the Contractor that he is required to obtain approval prior to subcontracting and that you have reservations that the proposed subcontractor will not be able to Provide the Works and it will potentially result in a further Defect. You could refuse, see cl 26.2.
In respect of the Defect correction measures being proposed by the Contractor (“patching plaster”) you will need to consider what is set out in the contract and on that basis what is acceptable.
Having checked the notifications given, I would suggest that you make a clear list of the issues and have a meeting with the Contractor to agree a solution or that you will have to engage others to correct the Defects.