The debrief serves to correct your aeronautical knowledge. There is more to life in aviation than just 'ticks in boxes' for passing exams.
However, the Examiner who marked your paper MUST enter the details on the PPL application form - it needs to have his/her signature and examiner number recorded. These will also be on your answer sheets - which you are not entitled to keep.
Examiners are appointed by the CAA to conduct examinations on their behalf. They cannot shrug shoulders on that responsibility. Unless it was the MD who conducted the examinations, it is the specific Examiner from whom the CAA should be seeking information. They should have his/her contact details on their database since it was they who appointed the Examiner....