Re: @Pompous Git - ?
Fortunately not. Most of the DL had occurred while connected to my home network. I also purchased another block of data to prevent getting into ridiculous data cost territory.
I suspect the DL rate from MS is deliberately throttled. The DL I had given my assent to took about a week over a 10 Mb/s link. The particularly galling aspect of this is that having DL'd the image and made a USB installer meant that the additional DL to the Zenbook was completely redundant even if I had decided to upgrade/downgrade [delete whichever is inapplicable] to W10.
And no, I did not know about MS pushing unrequested files until after I had returned from my holiday. In many ways I am now grateful that MS did this as it gave me the impetus to have another look at Linux. Happily I can run most of what I need under Wine and Mint 13 plays nice with my hardware.