thanks for that, I'll have to work through it

Sounds like you ended up in the Grub shell environment.
actually it was busybox (and that was referenced on one of those links, thanks!)
Also, a boot partition on a hard disk needs to have a specific bit set. This is normally managed by the installation software.
this is what I would have expected, but I'm going to have to work through this slowly cos I have no familiarity with nix setups.
I'm actually wondering if the setup isn't selecting the USB as the boot drive. I noticed in the manual partition setup that was the default, but i'll need to dig into it a bit further
All these installation issues make you see Linux from a not so flattering side.
it does kind of take the shine off all that 'easy to use' propaganda

But Windows 10 also comes with its own problems.
fair to say thats pretty standard for windows 'updates' so it probably doesn't come as a surprise to anyone.
FWIW the SSD I used came out of my old win10 desktop. The interesting bit is that the netbook booted into win10 straight away, no questions asked. Impressed me no end considering whats under the hood