With regards to performance testing:

The Contractor has no responsibility to notify the Owner that he is ready to execute the performance tests.

If the Owner does not or cannot attend the performance testing through no fault of the Contractor, the Owner cannot claim that the performance tests were not executed validly.

If the Works do not achieve the guaranteed performance and the Contractor executes remedial Works, the Employer cannot claim a retest.

The performance testing is to take place under the authority and direction of the owner.