Re: PPL Validity extended?
I suspect the latter.
Your source appears to be confusing the JAA-inflicted licence re-issue with Rating renewal.
If your PPL hasn't been used for more than 5 years, you will require to fly a Renewal Licensing Skill Test with a JAR-FCL Examiner after completing whatever refresher training you think you need to prepare yourself for the test.
There is no such thing as a PPL GFT.
There is no 'instructor sign-off' requirement.
After passing the Renewal LST, you will have to send off the forms to the CAA as an Examiner is not permitted to sign the 'Ratings - Certificate of Revalidation' page of your licence for Ratings which have lapsed by 5 years or more. You will have to pay for your licence accordingly - as well as the Rating variation fee as I understand it.