Right of Abode Advice

[essjay]

I would like to apply for a certificate of entitlement (ROA). I want to confirm my eligibility before I complete the application process.

Both my parents were born in Guyana in 1948 making them CUKCs. i currently have both their CUKC passports in my possession. Does this mean that they are considered "registered"? They immigrated to Canada in the late 50's, where I was born in '61. They acquired Canadian citizenship in the late '60s, I believe. my father worked in the UK for a period of 2 years. (I have his national insurance card).
Guyana gained independence in '66. According to the current UK guidelines, would I have clear eligibility for ROA status since at the time of my birth both parents were considered "registered" CUKCs?
What documentation should I submit to support my claim? I am reluctant to submit the original paperwork for fear of losing their info which would be impossible to replace so would it be worthwhile to make the application in Ottawa or is it recommended to make the submission directly to the home office.

Thanks in advance for the advice.

[JAJ]

Guyana was a colony (British Guiana) so it looks like your parents were CUKC by birth, not by registration.

Have you looked into whether or not they lost CUKC status when Guyana became independent? Did they become Guyana citizens and if so, did they retain any links to the United Kingdom or a place which remained a colony?