I do not think that you are eligible to register for British citizenship.
For a British national to register as a British citizen, s/he needs to never have had another citizenship. That is stated in the link that you posted yourself in the initial post of this thread.
The relevant section of the law that applies is
Section 4B of the British Nationality Act 1981 as amended.
4B - Acquisition by registration: certain persons without other citizenship
(1) This section applies to a person who has the status of—
- (d) British National (Overseas)
(2) A person to whom this section applies shall be entitled to be registered as a British citizen if—
- (a) he applies for registration under this section,
(b) the Secretary of State is satisfied that the person does not have, apart from the status mentioned in subsection (1), any citizenship or nationality, and
(c) the Secretary of State is satisfied that the person has not after the relevant day renounced, voluntarily relinquished or lost through action or inaction any citizenship or nationality
(3) For the purposes of subsection (2)(c), the “ relevant day ” means—
- (a) in the case of a person to whom this section applies by virtue of subsection (1)(d) only, 19th March 2009, and
(b) in any other case, 4th July 2002.
To the best of my knowledge, China regards all people of Chinese ethnicity resident in any part of China (including Hong Kong) as Chinese citizens. So, even were you to never have had a HKSAR passport, Chinese law would consider you a Chinese citizen. Which would mean that you would not meet the requirements of sub-section 2(b) quoted above.
The UK government has produced a short summary of what they believe is
Chinese nationality law and it is quite likely that the caseworker looking at your application would refer to it.
Mind you, I am not a lawyer, just somebody going by the language of the law and by what others have reported on these forums.
We have come across people who have been duped by their solicitors. So, I would suggest researching this yourself first before taking it forward.
I am not a lawyer or immigration advisor. My statements/comments do not constitute legal advice. E&OE. Please do not PM me for advice.