Applying via UKM Route - Guidance required

[nisheeb]

Hi All

Some guidance required please.

Mother - Born in British India 1943, then moved to Kenya with Parents (for work) in 1944. Mothers Parents and Grandparents all British Citizens too.

1955 in Mombasa, Kenya - Mother filled in application for the Registration as a Citizen of the United Kingdom and Colonies. Initial registration was stamped 29/10/1955 as a minor and then re-registered as an adult on 02/09/1966.

Mother has continuously held on to British Passport throughout her life. Married a Tanzanian citizen, moved from Kenya to Tanzania and has 4 children all before 1983.

Fastforward to 2001 til today - Mother now settled in UK.

1) Are children eligible for British Citizenship by descent as born to British Mother before 1983?

a) Son managed to get a BOC passport and has been in UK for last 6 years trying to get full citizenship so he can call his wife and kids over but to no avail. In this 6 years, boys have now gone over age of 18 (18, 20, 21) and do not want to leave boys behind).

2) Had son obtained full passport initially his kids would have been able to come over easily as all would have been under 18. Cannot leave boys behind, what is the best way forward?

All help appreciated.
Thanks
Nishee