format for affidavit

Hi,

does anyone have the format for affidavit for my friends case case where he was born in India, but travelled on mother's passport long time ago to UK and eventually got British citizenship and his 1st ever passport was a Uk passport, he never held Indian passport in his name.
The mother's passport with my friends name was submitted to Home Office during Naturalisation.

I am looking for the format but can't find it, also what will be best, to get it signed by notary or self certify and produce Indian birth certificate.

many thanks