Basically what I thought; I'll provide feedback once I 'know'.

BIOS doesn't provide UEFI, so that's not an issue, but this process (IAW Microsoft's guide) starts from within Windows, running the USB's setup.exe as an Administrator.

I may have previously left...

I have 1511 installed and hit the issue with a couple of updates not installing so I can't install the Anniversary and follow-on upgrade so, using the Media creation tool, I created the Win 10...