Adoption haven't been carried out under auspices Hague

[jphillips]

Hello everyone, can you please help me with some questions?
Here's the question:
I am Brazilian, 30 years old and I was adopted in 1996 at age 9 by a British man married to a Brazilian and resident of Brazil, my father has been living in Brazil since 1987. I recently tried to apply for the passport and it was refused, they claimed that I should present a "Certificate of Conformity of International Adoption", if I did not, my British citizenship wasn’t recognized by the UK because it would not fit the BNA 81 5 (1) http://www.legislation.gov.uk/ukpga/1981/61/section/1.
- My adoption was national (occurred in Brazil), so I could not have a certificate of conformity of international adoption according to the Hague Convention.
- At the time of my adoption Brazil was not a designated country (list of countries recognized by the UK where national adoptions are automatically recognized), which happened only in 2014 http://www.legislation.gov.uk/ukdsi/2013/9780111533437.
However, I made contact with the Brazilian judicial institution (CEJAI) responsible for overseeing and certifying international adoption and after analyzing my adoption process, issued a statement that the XXX adoption of XXX has become final and unappealable on date XXXX has terminated the pre-existing family bond.
My question is:
Will this statement be enough to persuade the HM Passport Office to recognize my citizenship?
If not, what is the best way forward for my situation?
I have already hired consultancies regulated by the OISC and the conclusions were not positive.
Should I apply for "Application for confirmation of British nationality status: form NS"?
My father lived in the United Kingdom for 30 years and never naturalized himself. His family lives in UK and he always stays in touch with their British relatives. With all of this:
Can he still be considered "habitually resident in the United Kingdom"?
P.S .: It is important to note that my father adopted 10 children and had a biological child. The biological son and one of the adopted daughters obtained the British passport, having their citizenship automatically recognized.

I will be very happy with any contribution!

[jphillips]

Correcting: never naturalized as a Brazilian *.

I am sharing the decision / letter from the Home Office so that you can see more clearly the reason for the refusal of the passport application.
[link removed by moderator- personal details included]