and issued me a valid licence
Neither an Instructor nor an Examiner have ever issued Licences - That has always been the CAA.
authorized CAA employees who have validated my credentials
worldpilot,
Are you confusing Instructors, Examiners and Authorised CAA Employees? They are not necessarily the same thing.
Although they are not (usually) employees of the CAA, Examiners have always been empowered to sign Rating Revalidations or Renewals (but not initial issues) on behalf of the CAA. Pre EASA Examiner Certificates specifically stated this authorisation.
A vast majority of an Examiner course is learning the paperwork requirements - Instructors (unless also Examiners) do not have that training and are not authorised to sign Rating 'certificates'.
Now that we are all EASA then Part-ARA applies, and I would refer 'worldpilot' to CAA Information Notice IN-2013/012 (which, as with all CAA documents, will not Copy and Paste
) where, in Section 1.3, it states: "Part-ARA Allows
Examiners to renew or revalidate ratings...."
Also look at the mass of
Examiner forms on the CAA website, eg SRG1157
Examiner's Report where it asks whether the
Examiner has signed the Rating's Page or not.
If you still think Instructors can sign to Revalidate or Renew Ratings then please tell us where this authorisation is stated - I cannot find it anywhere!