It's a little bit like that (having a punt)
Either way, as you suggest you will need to add good explanations.
If you decide to leave it blank, then there is a possible danger of having a well-meaning person adding Scotland, because that's what's on all the Internet Sites.
You could put Ireland or Northern Ireland and mark it as uncertain if you feel the circumstantial evidence is strong enough?
As I said good explanations either way.