"The UK Government has been keen to maintain a common travel area with Ireland (now an independent country within the EU) after Brexit, therefore it makes little sense for it to deny a retention of membership to an independent Scotland – unless through spite and vindictiveness. So Scottish and English citizens should be able to pass freely across the border, to work, shop in Berwick or Carlisle, or visit friends, though the position may differ for goods if Scotland rejoins the EU. As for family members becoming foreigners, well it was England that voted for that, and the Tory Government at Westminster have split and made foreigners of many family members who have lived, worked, paid taxes, raised children and contributed to communities and society in Scotland."
https://newsnet.scot