But this has to do solely with citizenship, right? I think FIFA has its own rules for eligibility in representing a particular country - citizenship alone is not always sufficient
I also think the Association’s have discretion to modify the home nations agreement (see bold section below) Since the Associations are bound by international law and the highest court in the UK, how could the Association’s legally deny an applicant under 4(c) without violating the law?
16 Nationality entitling players
to represent more than one Association
1 A Player who, under the terms of art. 15, is eligible to represent more than one Association on account of his nationality, may play in an international match for one of these Associations only if, in addition to having the relevant nationality, he fulfils at least one of the following conditions:
(a) He was born on the territory of the relevant Association;
(b) His biological mother or biological father was born on the territory of the relevant Association;
(c) His grandmother or grandfather was born on the territory of the relevant Association;
(d) He has lived continuously on the territory of the relevant Association for at least two years.
2 Regardless of par. 1 above,
Associations sharing a common nationality may make an agreement under which item (d) of par. 1 of this article is deleted completely or amended to specify a longer time limit. Such agreements shall be lodged with and approved by the Executive Committee.