Where is the box on the tax return to indicate a Scottish taxpayer? Surely HMRC haven’t made it anymore complicated than needs be?
Ah from the address
They will ignore the address and any white space notes. Scottish taxpayers are identified outside SA and updated automatically to the system so no matter what calculations you submit in your return there may be changes to the calculation later. Scottish taxpayers can have an address outside Scotland and not all taxpayers with Scottish addresses are Scottish taxpayers.
If you use commercial tax software it will have a flag you can set.