HKG3

First of all, if you want to register your children as British Citizens under section 3(2) of the BNA 1981, you must lived in the UK for three years - see page 9 below

https://www.gov.uk/government/upload...e_mar_2015.pdf

Great Grand Parents are too far back for your wife to claim British Citizenship

As to your own case, is there a possibility that you have some form of British nationality at the time of your birth from your biological mother? As I have very limited understanding how these things worked before the BNA 1981, I think BritInParis would be the best person to answer your question.

If you are the only British Citizen in the family, your wife and children can come to the UK if you meet the financial requirement for them. You will need to have a job earning £24800 per year, see the link below -

https://www.gov.uk/remain-in-uk-family/eligibility

You can use the Surinder Singh route in order to overcome the financial requirement. There are a number of posts in this forum that could give you more information.

Your children can qualify for ancestry visas (as one of their grandparent was a British Citizen born in the UK) when they become 17. This visa will enable them to work and stay in the UK for 5 years and could led to settlement.

BritInParis

As a Commonwealth citizen with a British-born mother (birth or adopted) you already have Right of Abode in the UK but not British citizenship.

In order to obtain British citizenship you could register under Section 4C of the British Nationality Act 1981 through either your birth or adopted mother. It may be easier to go through your birth mother however if you have your original birth certificate. This would give you British citizenship by descent which doesn't allow you to automatically pass on your citizenship to any children subsequently born outside the UK.

Alternatively you could move to the UK and naturalise under Section 6(1) BNA 1981 after five years of residence. This would give you British citizenship otherwise than by descent does allow you to automatically pass on your citizenship to any children subsequently born outside the UK.

In either scenario any children you have already had outside the UK and your wife would not immediately be eligible for citizenship but you could sponsor them for a visa to join you in the UK. Assuming your children were still under 18 then your children and wife would become eligible for citizenship after three and five years of residence respectively. They would become British citizens otherwise than by descent even if you were a British citizen by descent.

If your children are already over 18 then they would qualify for an ancestry visa through their British-born grandmother which, after five years of working in the UK, would allow them to naturalise under Section 6(1) BNA 1981 and become British citizens otherwise than by descent.

DavidOpp

Thank you HKG3 and BritInParis - I really appreciate your insight