Further to my above post, another Windows update sent the machine into repair mode, fortunately resolved by itself this time.
I never had problems like this with my previous versions, why can't the Beanbag Barons just @&%$@# leave perfectly adequate systems/interfaces alone. I can't find anything on Windows 11 that's more useful than W10 (or even XP and 7, come to that). If anything, it's more difficult to navigate through. It'll be a nightmare for those comfortable with the more-or-less consistent (simple) previous versions when W10 gets to it's 'end of life' retirement and this gets foisted on them.