I have been through to all the guidance notes, the last one on their website is updated on March 2019, and i have seen no changes under documentation. Neither i can find any type of letter of consent required in the guidance. My Son's case falls in the following category;
Applicant was born outside the UK and the
Falkland Islands on or after 1 January 1983,
or outside the UK and any qualifying British
overseas territory on or after 21 May 2002,
to a parent born in the UK or the Falkland
Islands (or, on/after 21 May 2002, any
qualifying British overseas territory) or to a
parent registered or naturalised in the UK
prior to the applicant’s birth
• Applicant’s full birth certificate
showing parents’ details,
• Parent’s marriage certificate (if
claiming through father and applicant
born before 1 July 2006), and
• Parent’s full birth certificate, registration
or naturalisation certificate
So only these documents are need:
1: full birth certificate. 2: Parents marriage certificate. 3: Father's Naturalisation Certificate.
i do not think there is any fourth document is required at all. Passport and 2 photographs are obviously standard and necessary. But for the letter of consent it is on the checklist as well as on the filled application form both.