NEC ECS: Compensation Event for not being able to complete works?

The normal construction sequence for the construction of gullies is to place the gully and risers up to cover level with the cover being adjusted to suit the final road surface level. On this particular (NEC3 Option B) project, to ensure full compaction of the road surface layers the Subcontractor were not allowed to construct the gully to full height, instead the Subcontractor were required to construct to the underside of tar level then after the tar has been placed return to break out the layers of tar and build up the gully to underside of cover level and place the cover.
The Subcontractor will issue a CE to seek to recover the cost of breaking the tar and raising the gully to the final level. an operation that the Subcontractor did not allow for within their tender.

Which clause should the Subcontractor quote to recover the costs associated?

Did the Subcontractor have an instruction to not finish the gullies? If you did then you can notify that this is a compensation event and any costs associated can be evaluated through the compensation event quotation process. If you didn’t have an instruction and you chose to do this off your own back then however much in good faith you did this you do not have a contractual remedy.

In any situation, your only means of recovery for anything not in the tender Price is if you can get them to agree a reason for a compensation event, and follow on with quotation and assessment to get it implemented.