In the KB article https://community.giffgaff.com/t5/Using-giffgaff/When-to-contact-an-agent/ta-p/9114714 the subcategory for Help regarding Removal of the Adult Content Bar https://support2.giffgaff.com/app/ask/Calls-texts-and-data/Controlling-Adult-Content/form/ is missing.
UPDATE: it is there but I couldn't see it!
It's there, under "Calls, Text & Data Issues (UK Only)"
Duh! I couldn't see it to save my life! ☹