Starting over with GIMP installation...

Juxtaposing you wanted to do a clean installation of the latest version, 2.10.8,
instead of the "sort of update" that I did yesterday. So in Win 10 you'd go and do an
uninstall of both GIMP and GMIC... You'd see it seems to progress normally - all the right
questions about your being sure; the assurance messages it has been completely removed...
- and then you check and find that a whole heap of it is still there, like plug-ins and GMIC
under ...\User...

It's not inspiring So now I'm going to manually delete all that before...