Not wanting to teach granny to suck eggs but do you know HMRC will add your State onto your multi-pensions annual "unearned" income gross and recalculate your code/liability....if it all triggers an annual gross above the current tax free trigger...whatever it is now.It wouldn't surprise me in the slightest if some believed the bit in bold, people can be easily led.
My 3 military pensions, injury compensation and in a few years my State Pension will be received whatever the fallout from independence SNP stylee, they're all UK governments domain. If however during the separation talks the UK gov decides to make the Scot Gov pay all these pensions etc, they still have to pass that money onto Scot Gov to pay out to recipients. What I would be concerned about is the amount of tax applied and whether what I currently receive free of tax continues that way (injury comp and relevant pensions etc), also the level at which tax kicks in could be quite damaging.
In short, they will back-door tax your State Pension.
I'd wager your code would be 520 or close like SWMBOs but that is entirely governed by specific & personal gross totals.