"Scots-Irish" seems to be a term used in the USA rather than here.
The SCots (apart from the Picts) came from Northern Ireland originally
anyway. I believe "Scots" originally meant "Irish".....
We're told here that 13-15 US presidents came from Northern Ireland
(mostly Antrim and Tyrone, where there is the Ulster-American
FOlk park incidentally), Kennedy and Reagan were the two US
presidents from a Southern Irish background.