Right, so I just did a thing. I backed up my NAND, formatted with TinyFormat, and used Decrypt9WIP to take the movable.sed from the formatted sysnand. Opened it in a HexEditor, and to my surprise it was a completely new movable.sed. I have only system transferred once, and I can confirm that this is a new movable.sed compared to both the consoles have used. I copied it over my LocalFriendCodeSeed, restored my old NAND, injected it, and I was allowed online.
I should also mention it was the 002-0102 ban code.