Supporting Documents for Certificate of Entitlement - Outside UK

Hello

I am planning to apply for Certificate of Entitlement from outside the UK via the online portal, however i cannot find the answer to the following questions:-
a. Except my local passport and my UK naturalization certificate, what other supporting documents do i need to include?
b. Obviously i need to send the original local passport but do i also need to include the original UK naturalization certificate? Being a very important document i do not want to lose it. Can i send an attested copy of it?

I was registered as a UK citizen recently but i do not have time to apply for British passport (takes 3 months) and saw the the Certificate of Entitlement is processed quickly (with in 3 weeks).

Anyone who has info on this or gone through the process by applying from OUTSIDE THE UK?

Thanks

How did you become a British citizen? Under Section 6(1) or Section 6(2) (married to a British citizen)?

If it is the former, I strongly advise not to apply for this from abroad as your future intentions may be called into question.

I became a British Citizen via 13(1) meaning "a person who has ceased to be a British citizen as a result of a declaration of renunciation shall be entitled, on an application for his registration as a British citizen"

What was the list of requirements you had to fulfill?