Confused about family's post-1997 status

THROUGH these columns, I would like to ask for some clarification from the Hong Kong Immigration Department and the Registration of Persons (Hong Kong Identity Cards) Section.

In the early 1960s, my late father (who had come to Hong Kong in the mid-'50s on an Indian passport) was naturalised by registration and obtained British nationality. Because India does not permit dual nationality, he gave up his Indian passport and thereafter only used his Hong Kong passport.

Being a minor at that time, my father also obtained British nationality for me.

I now hold a Hong Kong permanent identity card with an 'A' code, indicating 'Right of Abode in Hong Kong'.

My two teenage children, who were both born here, also hold Hong Kong permanent identity cards with an 'A' code, indicating 'Right of Abode in Hong Kong'. Does this permanent right of abode status change, if non-Chinese holders of Hong Kong permanent identity cards give up their BDTC or BN(O) passports for UK/American/Canadian passports? My widowed mother has lived in Hong Kong since the mid-1950s and does not envision going back to live in India, but she does not want to renounce her Indian citizenship. My wife, who has been in Hong Kong for almost 20 years, also does not want to give up her Indian citizenship. They have both been working in Hong Kong and have been contributing their share to Hong Kong's prosperity through regular payments of salaries tax.

How can they get 'permanent right of abode status' in Hong Kong, with an 'A' code on their Hong Kong identity cards, without having to apply for naturalisation? Because India still does not permit dual nationality, they would both automatically lose their Indian citizenship status, if they were to get Hong Kong passports. However, both of them have a 'U' code on their Hong Kong Identity Cards, indicating that they have 'unconditional right of entry into Hong Kong', provided they return to Hong Kong within 12 months of their last departure from Hong Kong.