UK government has all kinds of financial, visa and documentary requirements, effectively denying British descendants their right of return! For instance, someone with all 4 grandparents born in UK cannot just come home!
You may be interested in these active petitions
British descendants abroad with UK grandparents, must have employment with income of over £21,000 per year (more if married) plus many obstacles, like their own medical aid for 5 years and no access to social welfare for 5 years!
If your ancestors left Britain to fight for Britain, you have NO RIGHT TO RETURN, despite it being a Human Right according to United Nations.