Thank you for the link. That answers my grandparents question.
I have another question though, related to Q2 in the link.
Q2: Do I need to send my passport with my child passport application?
If your child has obtained BC by registration, your passport is not required. Just send his foreign passport (if has one),
birth certificate and the registration certificate.
According to the table at page 12 of the Guidance Notes, the birth certificate is not required...
https://www.gov.uk/government/uploads/s ... s_4_14.pdf
If you have recently applied for a child passport (registered citizen) did you send the birth certificate?
Did anyone send an application without the birth certificate, and was it accepted?