On the issue of permanent residence in Britain and British nationality, but I don't want to give up China nationality.

China passport can go back to China. Otherwise, those passports with black names have nothing on them and go back to China with the same passport.

However, if you have permanent residence, usually, you will have proof of permanent residence, such as a visa affixed to your passport, so that you can return to the UK conveniently. Isn't there a permanent visa on your mother's new passport? If not, you can use your China passport to return to China, but you may not be able to return to the UK.

Naturalization is nothing. If you live in China for a long time, you can also apply for permanent residence in China. Baidu can find the conditions, and over-age people can also apply for visa asylum for their families. In China, only China citizens with Macau or Hongkong status can have dual citizenship. Taiwan Province Province didn't take it back, so we won't discuss it.

You can change your name when you enter China, but you may not change your age.

After returning to China with a China passport, you can apply for a visa from another country and then return to the UK with a British passport from that country. But next time I go back to China, I will be in trouble.

Don't you have a lawyer? Why don't lawyers explain this to you? . . . . . . This can't be done.

Good luck.

Answer your supplementary question:

At present, China citizens who should be in the Mainland can only apply for permanent residence in Hong Kong if they have overseas permanent residence status.