Jct db 2016 eot

Working on a project under JCT DB 2016. In order to complete all of our works the Employer is required to gain certain approvals in order the Contractor to gain access to certain working areas. Each one of these approvals has not occurred in line with the programme milestones. Whilst we have re-sequenced our works to mitigate delays, an 8 week delay has become evident and agreed in principle. However, the Employer has one further point which they will not move on.
The Date for Completion of the Works in the Contract Particulars is stated as 3rd December. However on the programme, it states 3 items leading up to this date:

  1. Anticipated date of Practical Completion - 22/11/21
  2. O&M manual & H&S file (draft at PC - final version 2 weeks from PC) - 22/11/21 to 03/12/21
  3. Date for Completion - Contract Particulars - 03/12/21

The Employer is arguing that item 2 above is not required to gain Completion of the Works and therefore he should only be awarding a 6 week EOT, mitigating a further 2 weeks.

We have left the 3 items above as per the original contract programme and have argued, that to show the true delay this is the correct method in order to have the correct costs associated with the delay paid in full (i.e. the 8 weeks cost incurred in the middle of the programme where the delay actually happened).
Are we correct in our methodollogy?