Well, W8.1 full version i.e. mine to keep with the Key and 64 and 32 bit discs - turned up in an envelope so thin I thought it was junk mail. The shape of the discs was pressing through the thin cardboard.
It was sent by Microsoft.
I prepared the USB stick as described and simply copied the files onto it really not believing it would work. After all, didn't we have to have everything in its place in the DOS /s days? Anyway, it starts the instal procedure, but I stopped there because the notes said load the drivers at the same time for a smooth installation. Mmmm . . .
What, just plonk them on the USB as well like a post script? Curiouser and curiouser.