alwayslookingup
Good dit
You forgot to mention the Wales and Berwick Act 1746 in the union. As far as Wales goes ... it lasted until the Welsh Language Act in 1967.
As for my awkward little hometown (Berwick upon Tweed) the act was still in force until 1978 when Berwick was placed in England (for now as we say)
A hard border from Berwick to Carlisle would be a nightmare to set up and control. I suspect a return of Reiving would ensue.
You hit the nail squarely on the head with your post though.
I'm pretty sure that the RAF/Army/Navy will be in Scotland, whatever the politics, it just makes good military sense.