The ancestry visa applies to those Commonwealth, British Overseas, British Overseas Territories, British national (overseas) or Zimbabwe citizens who have a grandparent born in the UK, the Channel Islands or the Isle of Man.
Other requirements to consider:
The applicant must:
Validity and Extension
The ancestry visa is issued for a period of 5 years, and it can be extended for another 5 years although you may wish to look into the Indefinite Leave to Remain after 5 years of continuous stay in the UK.
Indefinite Leave to Remain
This visa leads to settlement after 5 years of continuous stay in the UK.