Thanks for the quick response. Yes, the certificate section 6 (2) states 'BRITISH CITIZEN'.

On this basis, it should be ok to apply online from outside the UK then? (sending Brazilian passport via post)

Hello everyone. My wife attended her citizenship ceremony and now has her certificate of naturalization. She completed this through the spouse route with myself, a UK citizen and we have a son, born in UK with British passport. This was done 3 months ago. I was relocated to Canada on a two year ...